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;
class dato {
 public:
  int x, y;
};
bool operator<(dato a, dato b) { return (a.y < b.y); }
int i, a, b, n;
long rest;
dato arr[500010];
int main() {
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d%d", &arr[i].x, &arr[i].y);
  sort(arr, arr + n);
  for (i = 0; i < n; i++)
    if (arr[i].x > b) {
      rest++;
      b = arr[i].y;
    }
  printf("%d\n", rest);
  scanf("%d", &n);
}
