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 N = 5e5 + 10, INF = 0x3f3f3f3f, MOD = 1e9 + 7;
int n;
pair<int, int> a[N];
int main() {
  ios_base::sync_with_stdio(0);
  while (scanf("%d", &n) == 1) {
    for (int i = 1; i <= n; ++i) scanf("%d%d", &a[i].second, &a[i].first);
    sort(a + 1, a + 1 + n);
    int ans = 0, r = 0;
    for (int i = 1; i <= n; ++i) {
      if (a[i].second > r) {
        ++ans;
        r = a[i].first;
      }
    }
    printf("%d\n", ans);
  }
  return 0;
}
