next(1,2).
next(2,3).
next(3,4).
next(4,5).
next(5,6).
next(6,7).
next(7,8).
next(8,9).
next(9,10).
next(10,11).
next(8,12).
next(12,13).
next(13,14).
next(14,15).
next(15,16).
next(16,17).
next(17,18).
next(15,19).
next(19,20).
next(20,21).
next(21,22).
next(22,23).
next(23,24).
next(24,25).
next(14,26).
next(26,27).
next(27,28).
next(28,29).
next(12,30).
next(30,31).
next(31,32).
next(32,33).
next(33,34).
next(34,35).
next(35,36).
next(36,37).
next(37,38).
next(38,39).
next(39,40).
next(37,41).
next(41,42).
next(42,43).
next(43,44).
next(44,45).
next(45,46).
next(46,47).
next(36,48).
next(48,49).
next(49,50).
next(50,51).
doAt(startflow,3).
doAt(a13,4).
doAt(a10,5).
doAt(a20,6).
doAt(a19,7).
doAt(a14,8).
doAt(a1,9).
doAt(endflow,10).
doAt(a16,12).
doAt(a23,13).
doAt(a21,14).
doAt(a6,15).
doAt(a18,16).
doAt(endflow,17).
doAt(a8,19).
doAt(a12,20).
doAt(a7,21).
doAt(a4,22).
doAt(a5,23).
doAt(endflow,24).
doAt(a17,26).
doAt(a25,27).
doAt(endflow,28).
doAt(a11,30).
doAt(a15,31).
doAt(a2,32).
doAt(a22,33).
doAt(a9,34).
doAt(a3,35).
doAt(a21,36).
doAt(a6,37).
doAt(a18,38).
doAt(endflow,39).
doAt(a8,41).
doAt(a12,42).
doAt(a7,43).
doAt(a4,44).
doAt(a5,45).
doAt(endflow,46).
doAt(a17,48).
doAt(a25,49).
doAt(endflow,50).
leftrightnexts(16,19).
leftrightnexts(15,26).
leftrightnexts(38,41).
leftrightnexts(37,48).
leftrightnexts(13,30).
leftrightnexts(9,12).