The input is:
5 5
0 0 2 0 2
0 0 0 0 0
0 0 0 0 0
0 0 0 5 0
1 0 0 4 0
Why the value of (3, 2) in the output is 7?  (point (i, j)
means the ith row, jth column). You see, (1, 3), (4, 4) and
(5, 1) are all three unit distance from (3, 2). I think it
must be 2 + 5 + 1 = 8.
Could anyone explain it to me?

Use bit 'or' instead of '+'.

I've got accepted. Thank you all the same.
> Use bit 'or' instead of '+'.