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;
pair<int, int> a[500009];
void initial() {}
void solve() {
  int n, i, p = 0;
  int ans = 0;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d %d", &a[i].second, &a[i].first);
  sort(a, a + n);
  for (i = 0; i < n; i++) {
    if (a[i].second > p) {
      ans++;
      p = a[i].first;
    }
  }
  printf("%d ", ans);
  printf("\n");
}
int main() {
  int i, T = 1;
  initial();
  for (i = 0; i < T; i++) {
    solve();
  }
  return 0;
}
