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 booking {
  int l, r;
};
bool logic(booking a, booking b) {
  if (a.r == b.r)
    return a.l < b.l;
  else
    return a.r < b.r;
}
int main() {
  int N;
  scanf("%d", &N);
  booking arr[500001];
  for (int i = 0; i < N; i++) {
    scanf("%d %d", &arr[i].l, &arr[i].r);
  }
  sort(arr, arr + N, logic);
  int last = -1, counter = 0;
  for (int i = 0; i < N; i++) {
    if (arr[i].l > last) {
      counter++;
      last = arr[i].r;
    }
  }
  printf("%d\n", counter);
  return 0;
}
