#include<iostream>
using namespace std;

int main()
{
	int n=0;
	int a[40]={0};
	while(cin>>a[n++]);n--;
	
	int maxn=1000000;
	bool p[maxn];
	for(int i=0;i<maxn;i++)
	{
		p[i]=1;
	}
	for(int i=2;i<maxn;i++)
	{
		for(int j=i+i;j<maxn;j+=i)
		{
			p[j]=0;
		}
	}
	
	for(int i=0,cnt=0;i<n;i++)
	{
		for(int j=2;j<=a[i];j++)
		{
			cnt+=p[j];
		}
		cout<<cnt<<endl;cnt=0;
	}
	return 0;
}
### Prompt

Your task is to create 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<iostream>
using namespace std;

int main()
{
	int n=0;
	int a[40]={0};
	while(cin>>a[n++]);n--;
	
	int maxn=1000000;
	bool p[maxn];
	for(int i=0;i<maxn;i++)
	{
		p[i]=1;
	}
	for(int i=2;i<maxn;i++)
	{
		for(int j=i+i;j<maxn;j+=i)
		{
			p[j]=0;
		}
	}
	
	for(int i=0,cnt=0;i<n;i++)
	{
		for(int j=2;j<=a[i];j++)
		{
			cnt+=p[j];
		}
		cout<<cnt<<endl;cnt=0;
	}
	return 0;
}
```