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