#include <iostream>
using namespace std;

inline bool check(int n)
{
	for (int i = 2; i*i <= n; i++)
	{
		if (n % i == 0) return false;
	}
	return true;
}

int main()
{
	int n[1000000] = {};
	int x;
	bool f;
	
	for (int i = 2; i <= 1000000; i++)
	{
		f = check(i);
		if (f == true) n[i] = n[i - 1] + 1;
		else n[i] = n[i - 1];
	}

	while (cin >> x)
		cout << n[x] << endl;
	return 0;
}

### Prompt

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

Write a program which reads an integer n and prints the number of prime numbers which are less than or equal to n. A prime number is a natural number which has exactly two distinct natural number divisors: 1 and itself. For example, the first four prime numbers are: 2, 3, 5 and 7.



Input

Input consists of several datasets. Each dataset has an integer n (1 ≤ n ≤ 999,999) in a line.

The number of datasets is less than or equal to 30.

Output

For each dataset, prints the number of prime numbers.

Example

Input

10
3
11


Output

4
2
5

### Response

```cpp
#include <iostream>
using namespace std;

inline bool check(int n)
{
	for (int i = 2; i*i <= n; i++)
	{
		if (n % i == 0) return false;
	}
	return true;
}

int main()
{
	int n[1000000] = {};
	int x;
	bool f;
	
	for (int i = 2; i <= 1000000; i++)
	{
		f = check(i);
		if (f == true) n[i] = n[i - 1] + 1;
		else n[i] = n[i - 1];
	}

	while (cin >> x)
		cout << n[x] << endl;
	return 0;
}

```