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(15,23). next(23,24). next(24,25). next(25,26). next(26,27). next(27,28). next(28,29). next(29,30). next(14,31). 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(32,40). next(40,41). next(41,42). next(42,43). next(43,44). next(44,45). next(45,46). next(46,47). next(47,48). doAt(startflow,4). doAt(a16,5). doAt(a7,6). doAt(a18,7). doAt(a22,8). doAt(a14,9). doAt(a21,10). doAt(a8,11). doAt(a24,12). doAt(a23,13). doAt(a10,14). doAt(a19,15). doAt(a17,16). doAt(a6,17). doAt(a1,18). doAt(a4,19). doAt(a11,20). doAt(endflow,21). doAt(a2,23). doAt(a12,24). doAt(a6,25). doAt(a1,26). doAt(a4,27). doAt(a11,28). doAt(endflow,29). doAt(a5,31). doAt(a25,32). doAt(a13,33). doAt(a6,34). doAt(a1,35). doAt(a4,36). doAt(a11,37). doAt(endflow,38). doAt(a15,40). doAt(a9,41). doAt(a20,42). doAt(a6,43). doAt(a1,44). doAt(a4,45). doAt(a11,46). doAt(endflow,47). leftrightnexts(16,23). leftrightnexts(33,40). leftrightnexts(15,31).