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;
class od {
 public:
  int s, e;
};
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<od> ods;
  for (od o; n--; ods.push_back(o)) cin >> o.s >> o.e;
  sort(ods.begin(), ods.end(), [](od &l, od &r) -> bool { return l.e < r.e; });
  auto i = unique(ods.begin(), ods.end(),
                  [](od &l, od &r) -> bool { return l.e >= r.s; });
  cout << i - ods.begin() << endl;
  return 0;
}
