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;
bool comp(pair<unsigned long long, unsigned long long> p1,
          pair<unsigned long long, unsigned long long> p2) {
  return p1.second < p2.second;
}
int main() {
  unsigned long long i, n, first, second, count = 1;
  vector<pair<unsigned long long, unsigned long long> > v;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> first >> second;
    v.push_back(make_pair(first, second));
  }
  sort(v.begin(), v.end(), comp);
  second = v[0].second;
  for (i = 1; i < v.size(); i++) {
    if (second < v[i].first) {
      second = v[i].second;
      count++;
    }
  }
  cout << count;
}
