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(11,12).
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(14,23).
next(23,24).
next(24,25).
next(25,26).
next(26,27).
next(27,28).
next(25,29).
next(29,30).
next(30,31).
next(31,32).
next(32,33).
next(33,34).
next(34,35).
next(29,36).
next(36,37).
next(37,38).
next(38,39).
next(39,40).
next(40,41).
next(24,42).
next(42,43).
doAt(startflow,4).
doAt(a5,5).
doAt(a16,6).
doAt(a12,7).
doAt(a25,8).
doAt(a15,9).
doAt(a13,10).
doAt(a17,11).
doAt(a9,12).
doAt(a22,13).
doAt(a3,14).
doAt(a18,15).
doAt(a19,16).
doAt(endflow,17).
doAt(a23,19).
doAt(a4,20).
doAt(endflow,21).
doAt(a1,23).
doAt(a2,24).
doAt(a24,25).
doAt(a10,26).
doAt(endflow,27).
doAt(a20,29).
doAt(a7,30).
doAt(a8,31).
doAt(a14,32).
doAt(a11,33).
doAt(endflow,34).
doAt(a6,36).
doAt(a8,37).
doAt(a14,38).
doAt(a11,39).
doAt(endflow,40).
doAt(endflow,42).
leftrightnexts(16,19).
leftrightnexts(30,36).
leftrightnexts(26,29).
leftrightnexts(25,42).
leftrightnexts(15,23).