10
7 2 8 9 10 4 3 6 5 
6 9 4 1 10 8 3 7 5 
1 10 5 8 9 7 4 6 2 
1 8 6 5 2 9 10 3 7 
7 3 4 10 9 6 8 1 2 
9 4 2 10 1 3 7 5 8 
4 1 3 10 6 5 8 2 9 
3 2 1 6 7 4 9 10 5 
1 8 2 4 10 7 3 6 5 
9 2 3 7 1 6 5 8 4 
forced 7 9
forced 3 5
forced 2 8