#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > dp;
bool good(pair<int, int> p) {
  if (dp.empty()) return false;
  if (p.first < dp.back().first || p.second > dp.back().second) return false;
  return true;
}
bool Ac(pair<int, int> p) {
  if (dp.empty()) return true;
  if (p.first > dp.back().second) return true;
  return false;
}
int main() {
  int n;
  cin >> n;
  vector<pair<int, int> > vec;
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    vec.push_back({x, y});
  }
  sort(vec.begin(), vec.end());
  for (int i = 0; i < n; i++) {
    if (good(vec[i])) {
      dp.pop_back();
      dp.push_back(vec[i]);
    } else if (Ac(vec[i])) {
      dp.push_back(vec[i]);
    }
  }
  cout << dp.size();
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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;
vector<pair<int, int> > dp;
bool good(pair<int, int> p) {
  if (dp.empty()) return false;
  if (p.first < dp.back().first || p.second > dp.back().second) return false;
  return true;
}
bool Ac(pair<int, int> p) {
  if (dp.empty()) return true;
  if (p.first > dp.back().second) return true;
  return false;
}
int main() {
  int n;
  cin >> n;
  vector<pair<int, int> > vec;
  for (int i = 0; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    vec.push_back({x, y});
  }
  sort(vec.begin(), vec.end());
  for (int i = 0; i < n; i++) {
    if (good(vec[i])) {
      dp.pop_back();
      dp.push_back(vec[i]);
    } else if (Ac(vec[i])) {
      dp.push_back(vec[i]);
    }
  }
  cout << dp.size();
}

```