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