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 habijabi {
  long int start_time, end_time;
} work[500500];
bool cmp(habijabi a, habijabi b) {
  if (a.end_time == b.end_time) {
    return a.start_time < b.start_time;
  }
  return a.end_time < b.end_time;
}
int main() {
  long int t, n, i, j;
  scanf("%ld", &n);
  for (i = 0; i < n; i++) {
    scanf("%ld %ld", &work[i].start_time, &work[i].end_time);
  }
  sort(work, work + n, cmp);
  int ans = 0, prev_end = -1;
  for (i = 0; i < n; i++) {
    if (work[i].start_time > prev_end) {
      ans++;
      prev_end = work[i].end_time;
    }
  }
  printf("%d\n", ans);
  return 0;
}
