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(8,19). 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(28,29). doAt(startflow,5). doAt(a10,6). doAt(a14,8). doAt(a2,9). doAt(a7,10). doAt(a13,11). doAt(a12,12). doAt(a1,13). doAt(a11,14). doAt(a4,15). doAt(a15,16). doAt(endflow,17). doAt(a8,19). doAt(a9,20). doAt(a5,21). doAt(a6,22). doAt(a12,23). doAt(a1,24). doAt(a11,25). doAt(a4,26). doAt(a15,27). doAt(endflow,28). compAt(a2,x3,7). leftrightnexts(9,19).