I've got AC then complete test for a<0 && b!=0:
1 999
2 999
3 0
4 1
5 2
answ 3...
Good Luck!

Edited by author 23.10.2011 01:27

Edited by author 23.10.2011 04:20

This is not correct test =)
In russian vertion of problem "В каждой из пяти строк входа находится пара целых положительных(!!!!) чисел, не превосходящих"

There are no points with negative x. Use assert to test such things.

Test 5 is likely about points that have the same x.