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>
const int MAXN = 500000 + 10;
struct node {
  int l, r;
};
node s[MAXN];
bool vis[MAXN];
bool cmp(const node &a, const node &b) { return a.r < b.r; }
int main(int argc, char const *argv[]) {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d %d", &s[i].l, &s[i].r);
  }
  memset(vis, false, sizeof(vis));
  std::sort(s, s + n, cmp);
  int ans = 1, cur = s[0].r;
  for (int i = 1; i < n; i++) {
    if (s[i].l > cur) {
      ans++;
      cur = s[i].r;
    }
  }
  printf("%d\n", ans);
  return 0;
}
