CHECKER 4 4
[0,0,1,0,-1,0] [1,0,2,0,1,1] [2,0,1,1,3,1] [3,0,2,0,3,1]
[1,1,0,2,1,2] [3,1,2,2,3,2]
[0,2,1,2,0,4] [1,2,2,2,1,3] [2,2,3,2,1,3] [3,2,4,2,3,4]
[1,3,0,4,1,4]