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C. History

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputPolycarpus 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.

Input

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.

Output

Print the only integer — the answer to the problem.

Examples

Input

5

1 10

2 9

3 8

4 7

5 6

Output

4

Input

5

1 100

2 50

51 99

52 98

10 60

Output

4

Input

1

1 1000000000

Output

0

Note

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.

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