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(21,25). next(25,26). next(26,27). 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(35,36). next(33,37). next(37,38). next(38,39). doAt(startflow,5). doAt(a25,8). doAt(a22,9). doAt(a10,10). doAt(a5,11). doAt(a12,12). doAt(a21,13). doAt(a3,14). doAt(a24,15). doAt(a9,16). doAt(a11,17). doAt(a14,18). doAt(a18,19). doAt(a2,20). doAt(a4,21). doAt(a20,22). doAt(endflow,23). doAt(a6,25). doAt(a23,26). doAt(a15,27). doAt(a17,28). doAt(endflow,29). doAt(a16,31). doAt(a8,32). doAt(a7,33). doAt(a1,34). doAt(endflow,35). doAt(a13,37). doAt(endflow,38). compAt(a25,x15,6). subsAt(a25,7). leftrightnexts(34,37). leftrightnexts(28,31). leftrightnexts(22,25).