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(9,13). next(13,14). next(14,15). next(15,16). next(16,17). next(14,18). next(18,19). next(19,20). next(20,21). next(21,22). next(22,23). next(20,24). next(24,25). 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(7,37). next(37,38). doAt(startflow,3). doAt(a9,5). doAt(a21,6). doAt(a15,7). doAt(a3,8). doAt(a7,9). doAt(a17,10). doAt(endflow,11). doAt(a19,13). doAt(a20,14). doAt(a25,15). doAt(endflow,16). doAt(a10,18). doAt(a13,19). doAt(a2,20). doAt(a16,21). doAt(endflow,22). doAt(a18,24). doAt(a23,25). doAt(a8,26). doAt(a24,27). doAt(a4,28). doAt(a5,29). doAt(a14,30). doAt(a22,31). doAt(a11,32). doAt(a12,33). doAt(a6,34). doAt(endflow,35). doAt(endflow,37). subsAt(a9,4). leftrightnexts(21,24). leftrightnexts(15,18). leftrightnexts(10,13). leftrightnexts(8,37).