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;
map<char, int> mp;
int main() {
  int x, c = 0, d = 0;
  cin >> x;
  pair<long long int, long long int> p[x];
  for (int i = 0; i < x; i++) cin >> p[i].first >> p[i].second;
  sort(p, p + x);
  reverse(p, p + x);
  for (int i = 0; i < x; i++) {
    d = 0;
    for (int j = i + 1; j < x; j++) {
      if (p[j].first >= p[i].first || p[j].second >= p[i].first)
        d++;
      else
        break;
    }
    c++;
    i += d;
  }
  cout << c;
}
