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
#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
int n;
pair<int, int> a[600000];
struct LIST {
  bool operator()(int x, int y) {
    return pair<int, int>(a[x].second, x) < pair<int, int>(a[y].second, y);
  }
};
set<int, LIST> s;
int main() {
  int i, j, k;
  cin >> n;
  for (i = 0; i < n; i++) scanf("%d%d", &a[i].first, &a[i].second);
  sort(a, a + n);
  for (i = 0; i < n; i++) s.insert(i);
  int ans = 0;
  int now = 0;
  while (s.size()) {
    ans++;
    int tar = *s.begin();
    while (now < n && a[now].first <= a[tar].second) s.erase(now), now++;
  }
  cout << ans;
  return 0;
}
