9

 3 3 3 3 3 3 3 3 3
 3 3 3 3 3 3 3 3 3
 3 3 3 3 3 3 3 3 3
 3 3 3 3 0 3 3 3 3
 0 3 3 3 0 3 3 3 0
 0 3 3 3 0 3 3 3 0
 0 0 0 0 0 0 0 0 0
 0 3 3 3 1 3 3 3 0
 1 0 1 0 2 0 1 0 1
