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;
const int maxn = 5e5 + 20;
struct Item {
  int a, b;
  Item() {}
  bool operator<(const Item &x) const {
    if (b == x.b) return a < x.a;
    return b < x.b;
  }
} items[maxn];
int main(void) {
  int n;
  while (scanf("%d", &n) == 1) {
    for (int i = 0; i < n; i++) scanf("%d%d", &items[i].a, &items[i].b);
    sort(items, items + n);
    int prev = 0, cnt = 0;
    for (int i = 0; i < n; i++)
      if (prev < items[i].a) {
        prev = items[i].b;
        cnt++;
      }
    printf("%d\n", cnt);
  }
  return 0;
}
