s1 <-> s7
s2 <-> s7
s2 <-> s8
s2 <-> s9
s6 <-> s12
s6 <-> s11
s6 <-> s10
s3 <-> s9
s3 <-> s7
s4 <-> s7
s5 <-> s7
s13 <-> s14
s7 <-> s13
s8 <-> s13
s9 <-> s13
s10 <-> s13
s14 <-> s15
s7 <-> s15
s14 <-> s16
s11 <-> s16
s12 <-> s16
s17 <-> s18
s14 <-> s17
s18 <-> s19
s18 <-> s20
s18 <-> s21
s18 <-> s22
s18 <-> s23
s18 <-> s24
s18 <-> s25
s18 <-> s26
s27 <-> s28
s18 <-> s27
s15 <-> s19
s15 <-> s20
s16 <-> s26
s28 <-> s29
s28 <-> s30
s28 <-> s31
s28 <-> s32
s20 <-> s30
s20 <-> s31
s20 <-> s32
s26 <-> s30
s33 <-> s34
s35 <-> s36
s37 <-> s38
s39 <-> s40
s41 <-> s42
s43 <-> s44
s45 <-> s46
s47 <-> s48
s49 <-> s50
s51 <-> s52
s29 <-> s37
s29 <-> s33
s30 <-> s35
s30 <-> s41
s30 <-> s47
s31 <-> s33
s31 <-> s45
s31 <-> s39
s32 <-> s47
s32 <-> s45
s32 <-> s35
s28 <-> s56
s28 <-> s49
s28 <-> s51
s28 <-> s53
s28 <-> s54
s28 <-> s55
s40 <-> s57
s53 <-> s57
s54 <-> s57
s52 <-> s57
s50 <-> s57
s56 <-> s57
s48 <-> s57
s30 <-> s43
s55 <-> s57
s42 <-> s57
s44 <-> s57
s38 <-> s57
s36 <-> s57
s34 <-> s57
s46 <-> s57