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;
int n, dp[500005], ans, q[500005], mx;
struct P {
  int l, r;
  bool friend operator<(P a, P b) {
    if (a.l != b.l) return a.l < b.l;
    return a.r < b.r;
  }
} a[500005];
struct F {
  int r, i;
  bool friend operator<(F a, F b) { return a.r < b.r; }
} b[500005];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &a[i].l, &a[i].r);
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; i++) {
    b[i].i = i;
    b[i].r = a[i].r;
  }
  sort(b + 1, b + n + 1);
  mx = 0;
  int j = 1;
  for (int i = 1; i <= n; i++) {
    while (j <= n && b[j].r < a[i].l) {
      mx = max(mx, dp[b[j].i]);
      j++;
    }
    dp[i] = mx + 1;
    ans = max(ans, dp[i]);
  }
  cout << ans;
  return 0;
}
