0 [2, 3, 1, 1]
0 [3, 1, 1]
0 [1, 1]
1 [3, 1]
0 [1]
1 [6, 1, 1]
0 [1, 1]
2 [3, 3, 1]
0 [3, 1]
0 [1]
1 [4]
! 1 [0]
! 2 [1, 0]
3
3 2 1