mirror of
https://github.com/apernet/OpenGFW.git
synced 2024-09-21 12:14:08 +08:00
518 lines
9.6 KiB
Go
518 lines
9.6 KiB
Go
package tcp
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import (
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"bytes"
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"github.com/apernet/OpenGFW/analyzer"
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)
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var _ analyzer.TCPAnalyzer = (*TrojanAnalyzer)(nil)
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// CCS stands for "Change Cipher Spec"
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var ccsPattern = []byte{20, 3, 3, 0, 1, 1}
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// TrojanAnalyzer uses length-based heuristics to detect Trojan traffic based on
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// its "TLS-in-TLS" nature. The heuristics are trained using a decision tree with
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// about 20k Trojan samples and 30k non-Trojan samples. The tree is then converted
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// to code using a custom tool and inlined here (isTrojanSeq function).
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// Accuracy: 1% false positive rate, 10% false negative rate.
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// We do NOT recommend directly blocking all positive connections, as this may
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// break legitimate TLS connections.
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type TrojanAnalyzer struct{}
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func (a *TrojanAnalyzer) Name() string {
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return "trojan"
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}
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func (a *TrojanAnalyzer) Limit() int {
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return 512000
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}
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func (a *TrojanAnalyzer) NewTCP(info analyzer.TCPInfo, logger analyzer.Logger) analyzer.TCPStream {
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return newTrojanStream(logger)
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}
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type trojanStream struct {
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logger analyzer.Logger
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first bool
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count bool
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rev bool
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seq [4]int
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seqIndex int
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}
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func newTrojanStream(logger analyzer.Logger) *trojanStream {
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return &trojanStream{logger: logger}
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}
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func (s *trojanStream) Feed(rev, start, end bool, skip int, data []byte) (u *analyzer.PropUpdate, done bool) {
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if skip != 0 {
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return nil, true
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}
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if len(data) == 0 {
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return nil, false
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}
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if s.first {
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s.first = false
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// Stop if it's not a valid TLS connection
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if !(!rev && len(data) >= 3 && data[0] >= 0x16 && data[0] <= 0x17 &&
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data[1] == 0x03 && data[2] <= 0x09) {
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return nil, true
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}
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}
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if !rev && !s.count && len(data) >= 6 && bytes.Equal(data[:6], ccsPattern) {
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// Client Change Cipher Spec encountered, start counting
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s.count = true
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}
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if s.count {
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if rev == s.rev {
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// Same direction as last time, just update the number
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s.seq[s.seqIndex] += len(data)
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} else {
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// Different direction, bump the index
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s.seqIndex += 1
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if s.seqIndex == 4 {
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return &analyzer.PropUpdate{
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Type: analyzer.PropUpdateReplace,
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M: analyzer.PropMap{
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"seq": s.seq,
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"yes": isTrojanSeq(s.seq),
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},
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}, true
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}
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s.seq[s.seqIndex] += len(data)
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s.rev = rev
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}
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}
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return nil, false
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}
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func (s *trojanStream) Close(limited bool) *analyzer.PropUpdate {
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return nil
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}
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func isTrojanSeq(seq [4]int) bool {
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length1 := seq[0]
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length2 := seq[1]
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length3 := seq[2]
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length4 := seq[3]
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if length2 <= 2431 {
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if length2 <= 157 {
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if length1 <= 156 {
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if length3 <= 108 {
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return false
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} else {
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return false
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}
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} else {
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if length1 <= 892 {
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if length3 <= 40 {
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return false
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} else {
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if length3 <= 788 {
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if length4 <= 185 {
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if length1 <= 411 {
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return true
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} else {
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return false
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}
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} else {
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if length2 <= 112 {
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return false
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} else {
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return true
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}
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}
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} else {
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if length3 <= 1346 {
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if length1 <= 418 {
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return false
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} else {
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return true
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}
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} else {
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return false
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}
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}
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}
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} else {
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if length2 <= 120 {
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if length2 <= 63 {
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return false
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} else {
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if length4 <= 653 {
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return false
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} else {
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return false
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}
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}
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} else {
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return false
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}
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}
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}
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} else {
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if length1 <= 206 {
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if length1 <= 185 {
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if length1 <= 171 {
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return false
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} else {
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if length4 <= 211 {
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return false
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} else {
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return false
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}
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}
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} else {
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if length2 <= 251 {
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return true
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} else {
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return false
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}
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}
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} else {
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if length2 <= 286 {
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if length1 <= 1123 {
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if length3 <= 70 {
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return false
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} else {
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if length1 <= 659 {
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if length3 <= 370 {
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return true
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} else {
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return false
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}
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} else {
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if length4 <= 272 {
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return false
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} else {
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return true
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}
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}
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}
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} else {
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if length4 <= 537 {
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if length2 <= 276 {
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if length3 <= 1877 {
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return false
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} else {
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return false
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}
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} else {
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return false
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}
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} else {
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if length1 <= 1466 {
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if length1 <= 1435 {
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return false
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} else {
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return true
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}
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} else {
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if length2 <= 193 {
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return false
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} else {
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return false
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}
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}
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}
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}
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} else {
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if length1 <= 284 {
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if length1 <= 277 {
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if length2 <= 726 {
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return false
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} else {
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if length2 <= 768 {
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return true
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} else {
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return false
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}
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}
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} else {
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if length2 <= 782 {
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if length4 <= 783 {
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return true
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} else {
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return false
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}
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} else {
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return false
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}
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}
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} else {
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if length2 <= 492 {
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if length2 <= 396 {
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if length2 <= 322 {
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return false
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} else {
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return false
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}
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} else {
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if length4 <= 971 {
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return false
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} else {
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return true
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}
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}
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} else {
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if length2 <= 2128 {
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if length2 <= 1418 {
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return false
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} else {
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return false
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}
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} else {
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if length3 <= 103 {
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return false
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} else {
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return false
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}
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}
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}
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}
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}
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}
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}
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} else {
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if length2 <= 6232 {
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if length3 <= 85 {
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if length2 <= 3599 {
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return false
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} else {
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if length1 <= 613 {
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return false
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} else {
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return false
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}
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}
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} else {
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if length3 <= 220 {
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if length4 <= 1173 {
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if length1 <= 874 {
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if length4 <= 337 {
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if length4 <= 68 {
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return true
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} else {
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return true
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}
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} else {
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if length1 <= 667 {
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return true
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} else {
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return true
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}
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}
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} else {
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if length3 <= 108 {
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if length1 <= 1930 {
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return true
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} else {
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return true
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}
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} else {
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if length2 <= 5383 {
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return false
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} else {
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return true
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}
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}
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}
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} else {
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return false
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}
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} else {
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if length1 <= 664 {
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if length3 <= 411 {
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if length3 <= 383 {
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if length4 <= 346 {
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return true
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} else {
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return false
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}
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} else {
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if length1 <= 445 {
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return true
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} else {
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return false
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}
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}
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} else {
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if length2 <= 3708 {
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if length4 <= 307 {
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return true
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} else {
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return false
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}
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} else {
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if length2 <= 4656 {
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return false
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} else {
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return false
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}
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}
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}
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} else {
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if length1 <= 1055 {
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if length3 <= 580 {
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if length1 <= 724 {
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return true
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} else {
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return false
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}
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} else {
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if length1 <= 678 {
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return false
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} else {
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return true
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}
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}
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} else {
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if length2 <= 5352 {
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if length3 <= 1586 {
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return false
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} else {
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return false
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}
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} else {
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if length4 <= 2173 {
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return true
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} else {
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return false
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}
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}
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}
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}
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}
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}
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} else {
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if length2 <= 9408 {
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if length1 <= 670 {
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if length4 <= 76 {
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if length3 <= 175 {
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return true
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} else {
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return true
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}
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} else {
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if length2 <= 9072 {
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if length3 <= 314 {
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if length3 <= 179 {
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return false
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} else {
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return false
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}
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} else {
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if length4 <= 708 {
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return false
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} else {
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return false
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}
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}
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} else {
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return true
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}
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}
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} else {
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if length1 <= 795 {
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if length2 <= 6334 {
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if length2 <= 6288 {
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return true
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} else {
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return false
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}
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} else {
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if length4 <= 6404 {
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if length2 <= 8194 {
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return true
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} else {
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return true
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}
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} else {
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if length2 <= 8924 {
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return false
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} else {
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return true
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}
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}
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}
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} else {
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if length3 <= 732 {
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if length1 <= 1397 {
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if length3 <= 179 {
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return false
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} else {
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return false
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}
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} else {
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if length1 <= 1976 {
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return false
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} else {
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return false
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}
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}
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} else {
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if length1 <= 2840 {
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if length1 <= 2591 {
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return false
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} else {
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return true
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}
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} else {
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return false
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}
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}
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}
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}
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} else {
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if length4 <= 30 {
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return false
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} else {
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if length2 <= 13314 {
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if length4 <= 1786 {
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if length2 <= 13018 {
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if length4 <= 869 {
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return false
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} else {
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return false
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}
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} else {
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return true
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}
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} else {
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if length3 <= 775 {
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return false
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} else {
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return false
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}
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}
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} else {
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if length4 <= 73 {
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return false
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} else {
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if length3 <= 640 {
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if length3 <= 237 {
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return false
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} else {
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return false
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}
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} else {
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if length2 <= 43804 {
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return false
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} else {
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return false
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}
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}
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}
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}
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}
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}
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}
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}
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}
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