A restaurant received n orders for the rental. Each rental order reserve the restaurant for a continuous period of time, the i-th order is characterized by two time values — the start time li and the finish time ri (li ≤ ri).

Restaurant management can accept and reject orders. What is the maximal number of orders the restaurant can accept?

No two accepted orders can intersect, i.e. they can't share even a moment of time. If one order ends in the moment other starts, they can't be accepted both.

Input

The first line contains integer number n (1 ≤ n ≤ 5·105) — number of orders. The following n lines contain integer values li and ri each (1 ≤ li ≤ ri ≤ 109).

Output

Print the maximal number of orders that can be accepted.

Examples

Input

2
7 11
4 7


Output

1


Input

5
1 2
2 3
3 4
4 5
5 6


Output

3


Input

6
4 8
1 5
4 7
2 5
1 3
6 8


Output

2
def R(): return map(int, input().split())
def I(): return int(input())
def S(): return str(input())

def L(): return list(R())

from collections import Counter 

import math
import sys


from itertools import permutations

n=I()
a=[]
for _ in range(n):
    b,c=R()
    a.append([c,b])

a.sort()
c,b=a[0]
cnt=1

for i in range(1,n):
    x,y=a[i]
    if y>c:
        c,b=x,y
        cnt+=1

print(cnt)
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