ROBOGAME- first problem

link- [link text][1]

For every robot which can move

I calculated lower and upper limit - marked its step - 1

if for any other robot , while marking movement if already has 1 (i.e clash is possible) print “unsafe”

if after marking every robot movement, there is no clash(1 is not overwritten) print “safe”.

Whats wrong?

Plz suggest any test case or fault in logic. As this problem went wrong for very large submissions during contest, I want to know.