0 [1, 2, 2, 1, 1]
1 [3, 1, 1]
0 [1, 1]
2 [1, 3, 1]
1 [2]
! 0 [0]
! 1 [0, 0]
! 0 [1, 0, 0]
4
1 2 1 1