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;
vector<pair<int, int> > ovect;
bool comp_func(pair<int, int> a, pair<int, int> b) {
  return a.second < b.second;
}
int main() {
  int n, i, j, k, count;
  pair<int, int> pr;
  while (cin >> n) {
    for (i = 0; i < n; i++) {
      cin >> j >> k;
      ovect.push_back(pair<int, int>(j, k));
    }
    sort(ovect.begin(), ovect.end(), comp_func);
    k = ovect[0].second;
    count = 1;
    for (i = 1; i < n; i++) {
      if (ovect[i].first > k) {
        count++;
        k = ovect[i].second;
      }
    }
    cout << count << endl;
    ovect.clear();
  }
  return 0;
}
