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 orde {
  int l;
  int r;
  bool b;
} order[500001];
void Q(int s, int t) {
  int m;
  orde p;
  int i = s;
  int j = t;
  m = order[(i + j) / 2].l;
  do {
    while (order[i].l < m) i++;
    while (order[j].l > m) j--;
    if (i <= j) {
      p = order[i];
      order[i] = order[j];
      order[j] = p;
      i++;
      j--;
    }
  } while (i <= j);
  if (i < t) Q(i, t);
  if (s < j) Q(s, j);
}
int main() {
  int i, j, k, n, t;
  cin >> n;
  for (i = 1; i <= n; i++) cin >> order[i].l >> order[i].r;
  Q(1, n);
  order[1].b = true;
  j = 1;
  t = 1;
  for (i = 2; i <= n; i++) {
    if (order[i].l > order[j].r) {
      order[i].b = true;
      j = i;
      t++;
    }
    if (order[j].r >= order[i].r) {
      order[j].b = false;
      order[i].b = true;
      j = i;
    }
  }
  cout << t;
}
