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 ≤ 10 5 ) 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 ≤ 10 9 ) — 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. In the first example the fifth event is contained in the fourth. Similarly, the fourth event is contained in the third, the third — in the second and the second — in the first. In the second example all events except the first one are contained in the first. In the third example only one event, so the answer is 0.