Polycarpus likes studying at school a lot and he is always diligent about his homework. Polycarpus has never had any problems with natural sciences as his great-great-grandfather was the great physicist Seinstein. On the other hand though, Polycarpus has never had an easy time with history.

Everybody knows that the World history encompasses exactly n events: the i-th event had continued from the year a_i to the year b_i inclusive (a_i < b_i). Polycarpus easily learned the dates when each of n events started and ended (Polycarpus inherited excellent memory from his great-great-granddad). But the teacher gave him a more complicated task: Polycaprus should know when all events began and ended and he should also find out for each event whether it includes another event. Polycarpus' teacher thinks that an event j includes an event i if a_j < a_i and b_i < b_j. Your task is simpler: find the number of events that are included in some other event.

The first input line contains integer n (1 ≤ n ≤ 10⁵) which represents the number of events. Next n lines contain descriptions of the historical events, one event per line. The i + 1 line contains two integers a_i and b_i (1 ≤ a_i < b_i ≤ 10⁹) — the beginning and the end of the i-th event. No two events start or finish in the same year, that is, a_i ≠ a_j, a_i ≠ b_j, b_i ≠ a_j, b_i ≠ b_j for all i, j (where i ≠ j). Events are given in arbitrary order.

Print the only integer — the answer to the problem.