#include <bits/stdc++.h>
using namespace std;
pair<int, int> od[500010];
int anw[2][500010];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> od[i].first >> od[i].second;
  sort(od, od + n);
  int s = 1;
  int l = od[0].first;
  int r = od[0].second;
  for (int i = 1; i < n; i++) {
    if (od[i].second <= r) {
      l = od[i].first;
      r = od[i].second;
    } else {
      if (od[i].first > r) {
        s++;
        l = od[i].first;
        r = od[i].second;
      }
    }
  }
  cout << s << endl;
}

### Prompt

In Cpp, your task is to solve the following problem:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
pair<int, int> od[500010];
int anw[2][500010];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> od[i].first >> od[i].second;
  sort(od, od + n);
  int s = 1;
  int l = od[0].first;
  int r = od[0].second;
  for (int i = 1; i < n; i++) {
    if (od[i].second <= r) {
      l = od[i].first;
      r = od[i].second;
    } else {
      if (od[i].first > r) {
        s++;
        l = od[i].first;
        r = od[i].second;
      }
    }
  }
  cout << s << endl;
}

```