#include <cstdio>
#include <memory.h>

int n;
int MAX_N=1000004;
bool DP[1000005] ;//素数リスト「素数じゃなかったらtrue」


int main()
{
	memset(DP,false,sizeof(DP));
	while(scanf("%d",&n)!=EOF)
	{
	 	int count=0;
		for(int i=1;i<=n;i++)
		{
			DP[0]=true;
			DP[1]=true;
			if(DP[i]==false)
			{
				count++;
				for(int j=i*2;j<MAX_N;j+=i)DP[j]=true;
			}
		}
		printf("%d\n",count);
	}
	return 0;
}
### Prompt

Your challenge is to write a CPP solution to the following problem:

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 <cstdio>
#include <memory.h>

int n;
int MAX_N=1000004;
bool DP[1000005] ;//素数リスト「素数じゃなかったらtrue」


int main()
{
	memset(DP,false,sizeof(DP));
	while(scanf("%d",&n)!=EOF)
	{
	 	int count=0;
		for(int i=1;i<=n;i++)
		{
			DP[0]=true;
			DP[1]=true;
			if(DP[i]==false)
			{
				count++;
				for(int j=i*2;j<MAX_N;j+=i)DP[j]=true;
			}
		}
		printf("%d\n",count);
	}
	return 0;
}
```