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 = 5e5 + 5;
int s, n;
pair<long long, long long> p[N];
bool com(pair<int, int> a, pair<int, int> b) {
  if (a.second == b.second)
    return a.first > b.first;
  else
    return a.second > b.second;
}
int main() {
  int n;
  cin >> n;
  vector<pair<int, int> > v;
  for (int f = 0; f < n; f++) {
    int a, b;
    cin >> a >> b;
    v.push_back(make_pair(b, a));
  }
  sort(v.begin(), v.end());
  int start = 0, ans = 0;
  for (int i = 0; i < n; i++) {
    if (v[i].second > start) {
      start = v[i].first;
      ans++;
    }
  }
  cout << ans << "\n";
}
