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 main() {
  int n;
  cin >> n;
  pair<int, int> a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i].first >> a[i].second;
  }
  auto cmp = [](pair<int, int> a, pair<int, int> b) -> bool {
    if (a.second != b.second) {
      return a.second < b.second;
    } else
      return a.first < b.first;
  };
  sort(a, a + n, cmp);
  int right = 0, left = 0;
  int ans = 0;
  for (auto x : a) {
    if (x.first > left) {
      left = x.second;
      ans++;
    }
  }
  cout << ans;
}
