1, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9

1, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9, 1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 2, 20, 3, 4, 5, 6, 7, 8, 9