next(1,2).
next(2,3).
next(3,4).
next(4,5).
next(5,6).
next(6,7).
next(7,8).
next(5,9).
next(9,10).
next(10,11).
next(11,12).
next(4,13).
next(13,14).
next(14,15).
next(15,16).
next(16,17).
next(17,18).
next(18,19).
next(19,20).
next(20,21).
next(21,22).
next(22,23).
next(23,24).
next(24,25).
next(22,26).
next(26,27).
next(27,28).
next(28,29).
next(29,30).
next(27,31).
next(31,32).
next(32,33).
next(17,34).
next(34,35).
next(35,36).
next(36,37).
next(37,38).
next(38,39).
next(39,40).
next(40,41).
next(41,42).
next(42,43).
next(43,44).
next(41,45).
next(45,46).
next(46,47).
next(47,48).
next(48,49).
next(46,50).
next(50,51).
next(51,52).
doAt(startflow,3).
doAt(a7,4).
doAt(a14,5).
doAt(a13,6).
doAt(endflow,7).
doAt(a18,9).
doAt(a6,10).
doAt(endflow,11).
doAt(a11,13).
doAt(a8,14).
doAt(a4,15).
doAt(a10,16).
doAt(a15,17).
doAt(a9,18).
doAt(a5,19).
doAt(a22,20).
doAt(a21,21).
doAt(a20,22).
doAt(a17,23).
doAt(endflow,24).
doAt(a19,26).
doAt(a16,27).
doAt(a2,28).
doAt(endflow,29).
doAt(a25,31).
doAt(endflow,32).
doAt(a24,34).
doAt(a1,35).
doAt(a23,36).
doAt(a12,37).
doAt(a5,38).
doAt(a22,39).
doAt(a21,40).
doAt(a20,41).
doAt(a17,42).
doAt(endflow,43).
doAt(a19,45).
doAt(a16,46).
doAt(a2,47).
doAt(endflow,48).
doAt(a25,50).
doAt(endflow,51).
leftrightnexts(6,9).
leftrightnexts(28,31).
leftrightnexts(23,26).
leftrightnexts(47,50).
leftrightnexts(42,45).
leftrightnexts(18,34).
leftrightnexts(5,13).