OJ Board

I do not understand why I keep getting "Wrong Answer" with this code.

It produces the right output for all samples I've seen, including ones posted here. In anyone can help, I'd appreciate it. :)

sample in
10 20
20 10
1 1
1 2
1 3
1 4
2 2
2 3
2 1
3 1
1 1000000
1 10
100 200
201 210
900 1000 ...