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(18,19).
next(19,20).
next(20,21).
next(21,22).
next(22,23).
next(23,24).
next(24,25).
next(25,26).
next(23,27).
next(27,28).
next(28,29).
next(29,30).
next(27,31).
next(31,32).
next(32,33).
next(33,34).
next(34,35).
next(32,36).
next(36,37).
next(37,38).
next(38,39).
next(39,40).
next(40,41).
next(37,42).
next(42,43).
next(43,44).
next(44,45).
next(45,46).
next(42,47).
next(47,48).
next(48,49).
next(49,50).
doAt(startflow,7).
doAt(a20,10).
doAt(a6,11).
doAt(a14,14).
doAt(a5,16).
doAt(a10,17).
doAt(a22,18).
doAt(a21,19).
doAt(a4,20).
doAt(a13,21).
doAt(a8,22).
doAt(a25,23).
doAt(a12,24).
doAt(endflow,25).
doAt(a7,27).
doAt(a3,28).
doAt(endflow,29).
doAt(a11,31).
doAt(a2,32).
doAt(a24,33).
doAt(endflow,34).
doAt(a15,36).
doAt(a18,37).
doAt(a23,38).
doAt(a9,39).
doAt(endflow,40).
doAt(a16,42).
doAt(a19,43).
doAt(a9,44).
doAt(endflow,45).
doAt(a17,47).
doAt(a9,48).
doAt(endflow,49).
compAt(a6,x12,9).
compAt(a14,x9,13).
compAt(a5,x20,15).
subsAt(a20,8).
subsAt(a14,12).
leftrightnexts(43,47).
leftrightnexts(38,42).
leftrightnexts(33,36).
leftrightnexts(28,31).
leftrightnexts(24,27).