#include <bits/stdc++.h>
using namespace std;
const int MaxN = 5e5;
int n;
struct pp {
  int x;
  int y;
} a[MaxN + 5];
bool cmp(pp a, pp b) { return a.y < b.y; }
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d%d", &a[i].x, &a[i].y);
  sort(a, a + n, cmp);
  int cnt = 0;
  int k = a[0].y;
  for (int i = 1; i < n; i++) {
    if (a[i].x <= k)
      cnt++;
    else
      k = a[i].y;
  }
  printf("%d\n", n - cnt);
  return 0;
}

### Prompt

Develop a solution in cpp 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;
const int MaxN = 5e5;
int n;
struct pp {
  int x;
  int y;
} a[MaxN + 5];
bool cmp(pp a, pp b) { return a.y < b.y; }
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d%d", &a[i].x, &a[i].y);
  sort(a, a + n, cmp);
  int cnt = 0;
  int k = a[0].y;
  for (int i = 1; i < n; i++) {
    if (a[i].x <= k)
      cnt++;
    else
      k = a[i].y;
  }
  printf("%d\n", n - cnt);
  return 0;
}

```