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;
struct tp {
  int l, r;
};
int n;
vector<tp> t;
bool comp(tp a, tp b) { return a.l < b.l or a.l == b.l and a.r < b.r; }
int main() {
  cout.sync_with_stdio(false);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int l, r;
    cin >> l >> r;
    t.push_back({l, r});
  }
  sort(t.begin(), t.end(), comp);
  int cl = -1;
  int cr = -1;
  int ans = 0;
  for (int i = 0; i < t.size(); i++) {
    if (t[i].l > cr) {
      ans += 1;
      cl = t[i].l;
      cr = t[i].r;
    } else if (t[i].l <= cr and t[i].r > cr) {
      continue;
    } else if (t[i].l <= cr and t[i].r <= cr) {
      cl = t[i].l;
      cr = t[i].r;
    }
  }
  cout << ans << endl;
  return 0;
}
