"*(*(ab)c)ab*(ab)"
success (0, (a, 1, 1)) (1, (b, 2, 2)) (2, (0, 3)) (3, (4, 4)) (4, (c, 5, 5)) (5, (0, 6)) (6, (7, 7)) (7, (a, 8, 8)) (8, (b, 9, 9)) (9, (a, 10, 10)) (10, (b, 11, 11)) (11, (9, 12)) (12, (13, 13)) (13, (0, 0))