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;
const int MAX = 500001;
struct para {
  int a, b;
};
inline bool cmp(para a, para b) { return a.b < b.b; }
int n, l, cnt;
para arr[MAX];
int main() {
  ios::sync_with_stdio(0);
  cin >> n;
  for (int i = 0; i < n; i++) cin >> arr[i].a >> arr[i].b;
  sort(arr, arr + n, cmp);
  int i = 0;
  while (i < n) {
    cnt++;
    l = arr[i].b;
    while (l >= arr[i].a && i < n) ++i;
  }
  cout << cnt;
  return 0;
}
