9
0 0 0 7 0 3 0 2 5
2 3 0 0 0 5 0 0 6
0 0 4 0 0 6 0 3 0
9 0 1 0 6 0 0 0 4
0 4 0 8 7 1 0 9 0
7 0 0 0 5 0 6 0 3
0 1 0 9 0 0 2 0 0
3 0 0 5 0 0 0 8 1
4 2 0 6 0 8 0 0 0