#include <bits/stdc++.h>
using namespace std;
struct order {
  int begin, end;
} m[500005];
bool cmp(const order a, const order b) { return a.end < b.end; }
int main() {
  int n;
  while (scanf("%d", &n) != EOF) {
    for (int i = 0; i < n; i++) {
      scanf("%d %d", &m[i].begin, &m[i].end);
    }
    sort(m, m + n, cmp);
    int end = 0, count = 1;
    end = m[0].end;
    for (int i = 0; i < n; i++) {
      if (m[i].begin > end) {
        count++;
        end = m[i].end;
      }
    }
    printf("%d\n", count);
  }
}

### Prompt

Construct a CPP code solution to the problem outlined:

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;
struct order {
  int begin, end;
} m[500005];
bool cmp(const order a, const order b) { return a.end < b.end; }
int main() {
  int n;
  while (scanf("%d", &n) != EOF) {
    for (int i = 0; i < n; i++) {
      scanf("%d %d", &m[i].begin, &m[i].end);
    }
    sort(m, m + n, cmp);
    int end = 0, count = 1;
    end = m[0].end;
    for (int i = 0; i < n; i++) {
      if (m[i].begin > end) {
        count++;
        end = m[i].end;
      }
    }
    printf("%d\n", count);
  }
}

```