next(1,2).
next(2,3).
next(3,4).
next(4,5).
next(5,6).
next(6,7).
next(7,8).
next(4,9).
next(9,10).
next(10,11).
next(11,12).
next(12,13).
next(13,14).
next(11,15).
next(15,16).
next(16,17).
next(17,18).
next(18,19).
next(19,20).
next(20,21).
next(21,22).
next(19,23).
next(23,24).
next(24,25).
next(25,26).
next(26,27).
next(27,28).
next(28,29).
next(29,30).
next(30,31).
next(31,32).
next(9,33).
next(33,34).
next(34,35).
next(35,36).
next(36,37).
next(37,38).
next(38,39).
next(36,40).
next(40,41).
next(41,42).
next(42,43).
next(43,44).
next(44,45).
next(45,46).
next(46,47).
next(44,48).
next(48,49).
next(49,50).
next(50,51).
next(51,52).
next(52,53).
next(53,54).
next(54,55).
next(55,56).
next(56,57).
doAt(startflow,3).
doAt(a5,4).
doAt(a13,5).
doAt(a18,6).
doAt(endflow,7).
doAt(a22,9).
doAt(a10,10).
doAt(a8,11).
doAt(a16,12).
doAt(endflow,13).
doAt(a3,15).
doAt(a20,16).
doAt(a4,17).
doAt(a1,18).
doAt(a19,19).
doAt(a9,20).
doAt(endflow,21).
doAt(a25,23).
doAt(a11,24).
doAt(a17,25).
doAt(a24,26).
doAt(a14,27).
doAt(a2,28).
doAt(a12,29).
doAt(a15,30).
doAt(endflow,31).
doAt(a23,33).
doAt(a7,34).
doAt(a6,35).
doAt(a8,36).
doAt(a16,37).
doAt(endflow,38).
doAt(a3,40).
doAt(a20,41).
doAt(a4,42).
doAt(a1,43).
doAt(a19,44).
doAt(a9,45).
doAt(endflow,46).
doAt(a25,48).
doAt(a11,49).
doAt(a17,50).
doAt(a24,51).
doAt(a14,52).
doAt(a2,53).
doAt(a12,54).
doAt(a15,55).
doAt(endflow,56).
leftrightnexts(20,23).
leftrightnexts(12,15).
leftrightnexts(45,48).
leftrightnexts(37,40).
leftrightnexts(10,33).
leftrightnexts(5,9).