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 comment(linker, "/STACK:1024000000,1024000000")
using namespace std;
const int maxn = 500005;
struct H {
  int l, r;
  friend bool operator<(const H x, const H y) { return x.r < y.r; }
} a[maxn];
int main() {
  int n;
  while (~scanf("%d", &n)) {
    for (int i = 0; i < n; i++) {
      scanf("%d%d", &a[i].l, &a[i].r);
    }
    sort(a, a + n);
    int ans = 0;
    int mxx = 0;
    for (int i = 0; i < n; i++) {
      if (a[i].l > mxx) {
        ans++;
        mxx = a[i].r;
      }
    }
    cout << ans << endl;
  }
  return 0;
}
