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 fox {
  int s;
  int e;
};
bool cmp(fox x, fox y) {
  if (x.e == y.e)
    return x.s < y.s;
  else
    return x.e < y.e;
}
fox a[500005];
int main() {
  int i, last, num, n;
  while (scanf("%d", &n) != EOF) {
    last = -1;
    num = 0;
    for (i = 0; i < n; i++) scanf("%d %d", &a[i].s, &a[i].e);
    sort(a, a + n, cmp);
    for (i = 0; i < n; i++) {
      if (a[i].s > last) {
        num++;
        last = a[i].e;
      }
    }
    printf("%d\n", num);
  }
  return 0;
}
