3
step
0
1
0
1
0
0
0
1
0
3
0
0
3
0
0
1
0
1
1
1
2
2
1
5
2
1
2
1
3
3
1
2
2
2
1
2
2
1
1
2
2
0
1
1
6
1
2
1
2
2
2
2
3
1
2
2
2
1
3