[[9, 6, 7, 8], [6, 9, 7, 8], [6, 7, 8, 9], [9, 6], [6, 9], [9]]
[[], [4], [3], [4, 5], [3, 5], [3, 4]]
[[6], [6, 4], [3, 6], [6, 4, 5], [3, 6, 5], [3, 4, 6]]