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
 3 3 3 0 0 0 3 3 3
 3 3 0 0 0 0 0 3 3
 3 0 0 0 0 0 0 0 3
 0 0 0 0 0 0 0 0 0
 3 3 3 3 3 3 3 3 3
