137_C. History
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 ai to the year bi inclusive (ai < bi). 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 aj < ai and bi < bj. 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 ≤ 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 ai and bi (1 ≤ ai < bi ≤ 109) — the beginning and the end of the i-th event. No two events start or finish in the same year, that is, ai ≠ aj, ai ≠ bj, bi ≠ aj, bi ≠ bj 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.
```python
import sys
import math

n=int(input())
k=[]
for i in range(n):
    a,b=map(int,input().split())
    k.append((a,b))
k.sort()
t,con=0,0
for (a,b) in k:
    if(b<t):
        con+=1
    else:
        t=b
print(con)
```