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
import sys
input=sys.stdin.buffer.readline

n=int(input())
arr=[]
for i in range(n):
    l,r=map(int,input().split())
    arr.append([l,r])
arr.sort()
count=-1
arr.append([1000000000000,100000000000000])
mini=-1
for i in range(n+1):
    l,r=arr[i]
    if l > mini:
        count+=1
        mini=r
        continue
    mini=min(mini,r)

print(count)