x1 = x1
x2 = x2
x3 = x6
x4 = x5
x5 = x7
x6 = x8
x7 = x16
x8 = x15
x9 = x9
x10 = x11
x11 = x10
x12 = x12
x13 = x29
x14 = x30
x15 = x39
x16 = x46
x17 = x40
x18 = x45
x19 = x41
x20 = x44
x21 = x18
x22 = x17
x23 = x14
x24 = x22
x25 = x32
x26 = x13
x27 = x20
x28 = x21
x29 = x23
x30 = x27
x31 = x24
x32 = x25
x33 = x34
x34 = x36
x35 = x42
x36 = x37
x37 = x47
x38 = x48
x39 = x52
x40 = x51
x41 = x50
x42 = x53
x43 = x54
x44 = x55
x45 = x60
x46 = x59
x47 = x57
x48 = x61
x49 = x62
x50 = x63
x51 = x65
x52 = x68
x53 = x35
x54 = x28
x55 = x31
x56 = x56
x57 = x43
x58 = x3
x59 = x58
x60 = x4
x61 = x26
x62 = x49
x63 = x33
x64 = x64
x65 = x19
x66 = x38
x67 = x66
x68 = x67