I found my mistake. Helpfull test:
4
1 2
3 100
4 5
6 7
2
1
7
ans:
1
4

HINT:This problem can be solved O(n) with stack.

Edited by author 31.08.2016 10:07

Try to use 'longint' instead of 'int64'. In some problems it helps if you have WA.

thanks

Thank you so much for the test!