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
"""
Codeforces Testing Round #12

Problem 597B. Restaurant

@author yamaton
@date 2015-11-11
"""

import math
import operator
import random
import sys
import functools
import collections


def solve(pairs):
    pairs.sort(key=operator.itemgetter(1))
    progress = -1
    cnt = 0
    for (s, f) in pairs:
        if progress < s:
            progress = f
            cnt += 1
    return cnt


def solve0(pairs):
    pairs.sort()
    d = collections.defaultdict(int)
    maxval = 0
    for (s, f) in pairs:
        d[f] = 1 + max((d[k] for k in d.keys() if k < s), default=0)
        maxval = max(maxval, d[f])
    return maxval


def p(*args, **kwargs):
    return print(file=sys.stderr, *args, **kwargs)


def main():
    n = int(input())
    pairs = [tuple(int(i) for i in input().strip().split()) for _ in range(n)]
    result = solve(pairs)
    print(result)


if __name__ == '__main__':
    main()
