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 N = 512345;
int read() {
  int x;
  scanf("%d", &x);
  return x;
}
int l[N], r[N];
vector<int> v[2 * N];
int a[N * 2];
int main() {
  int n, m = 1e6, i, j;
  cin >> n;
  map<int, int> mp;
  for (i = 1; i <= n; i++) {
    l[i] = read();
    mp[l[i]];
    r[i] = read();
    mp[r[i]];
  }
  int k = 0;
  for (map<int, int>::iterator i = mp.begin(); i != mp.end(); i++)
    (*i).second = ++k;
  for (i = 1; i <= n; i++) {
    l[i] = mp[l[i]];
    r[i] = mp[r[i]];
    v[r[i]].push_back(l[i]);
  }
  for (i = 1; i <= m; i++) {
    a[i] = a[i - 1];
    for (j = 0; j < v[i].size(); j++) {
      a[i] = max(a[i], a[v[i][j] - 1] + 1);
    }
  }
  cout << a[m];
}
