[(1, 1), (1, 2), (2, 3), (2, 4), (1, 5), (2, 6), (1, 7)]
[(1, 1), (1, 2), (1, 5), (1, 7), (2, 3), (2, 4), (2, 6)]
(1, 1, 1, 1, 2, 2, 2) (1, 2, 5, 7, 3, 4, 6)
1 ,  remaining: 3
1 2
1 3
1 4
1 1 2