5 12
0 0 -1 2 -1 0 0 0 -1 2 -1 0
0 0 2 -1 -1 0 0 0 2 -1 -1 0
0 1 0 0 0 1 1 0 -1 -1 -1 0
-1 -1 0 0 0 2 -1 -1 0 0 0 2
-1 2 0 0 0 -1 -1 2 0 0 0 -1
