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(8,12). next(12,13). next(13,14). next(14,15). next(12,16). next(16,17). next(17,18). next(18,19). next(19,20). next(17,21). 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(30,31). next(31,32). next(32,33). 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). doAt(startflow,4). doAt(a2,7). doAt(a6,8). doAt(a25,9). doAt(endflow,10). doAt(a8,12). doAt(a22,13). doAt(endflow,14). doAt(a9,16). doAt(a15,17). doAt(a18,18). doAt(endflow,19). doAt(a1,21). doAt(a5,22). doAt(endflow,23). doAt(a7,25). doAt(a21,26). doAt(a13,27). doAt(a20,28). doAt(a14,29). doAt(a4,30). doAt(a3,31). doAt(a24,32). doAt(a23,33). doAt(a19,34). doAt(a10,35). doAt(a16,36). doAt(a17,37). doAt(endflow,38). doAt(a12,40). doAt(endflow,41). compAt(a2,x9,5). subsAt(a2,6). leftrightnexts(37,40). leftrightnexts(22,25). leftrightnexts(18,21). leftrightnexts(13,16). leftrightnexts(9,12).