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>
using namespace std;
int n;
pair<int, int> a[500005];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i].first >> a[i].second;
  }
  sort(a + 1, a + n + 1);
  vector<pair<int, int> > ans;
  ans.push_back(pair<int, int>(a[1].first, a[1].second));
  for (int i = 2; i <= n; i++) {
    pair<int, int> res = ans.back();
    if (a[i].first > res.second)
      ans.push_back(pair<int, int>(a[i].first, a[i].second));
    else {
      if (a[i].second < res.second) {
        ans.pop_back();
        ans.push_back(pair<int, int>(a[i].first, a[i].second));
      }
    }
  }
  cout << ans.size();
  return 0;
}
