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(8,14). 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(26,27). next(23,28). next(28,29). 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(41,42). doAt(startflow,4). doAt(a10,6). doAt(a9,7). doAt(a16,8). doAt(a25,9). doAt(a11,10). doAt(a18,11). doAt(endflow,12). doAt(a3,14). doAt(a15,15). doAt(a7,16). doAt(a5,17). doAt(a1,18). doAt(a13,19). doAt(a21,20). doAt(a23,21). doAt(a20,22). doAt(a8,23). doAt(a14,24). doAt(a18,25). doAt(endflow,26). doAt(a12,28). doAt(a19,29). doAt(a17,30). doAt(a24,31). doAt(a6,32). doAt(a18,33). doAt(endflow,34). doAt(a2,36). doAt(a22,37). doAt(a24,38). doAt(a6,39). doAt(a18,40). doAt(endflow,41). compAt(a10,x13,5). leftrightnexts(30,36). leftrightnexts(24,28). leftrightnexts(9,14).