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 a {
  long long x, y;
};
a p[500005];
bool cmp(a q, a w) {
  if (q.y == w.y)
    return q.x < w.x;
  else
    return q.y < w.y;
}
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> p[i].x >> p[i].y;
  sort(p, p + n, cmp);
  long long ans = 0, flag = -1 << 9;
  for (int i = 0; i < n; i++) {
    if (p[i].x > flag) {
      ans++;
      flag = p[i].y;
    } else
      continue;
  }
  cout << ans << endl;
}
