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(11,15). 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(27,28). next(24,29). next(29,30). next(30,31). next(31,32). next(32,33). next(29,34). next(34,35). next(35,36). next(36,37). next(37,38). next(34,39). next(39,40). next(40,41). next(41,42). doAt(startflow,4). doAt(a20,6). doAt(a5,7). doAt(a9,8). doAt(a6,9). doAt(a3,10). doAt(a1,11). doAt(a18,12). doAt(endflow,13). doAt(a11,15). doAt(a21,16). doAt(a19,17). doAt(a14,18). doAt(a12,19). doAt(a10,20). doAt(a15,21). doAt(a13,22). doAt(a2,23). doAt(a4,24). doAt(a24,25). doAt(a23,26). doAt(endflow,27). doAt(a8,29). doAt(a25,30). doAt(a23,31). doAt(endflow,32). doAt(a22,34). doAt(a17,35). doAt(a23,36). doAt(endflow,37). doAt(a7,39). doAt(a23,40). doAt(endflow,41). compAt(a20,x1,5). leftrightnexts(35,39). leftrightnexts(30,34). leftrightnexts(25,29). leftrightnexts(12,15).