#include <iostream>
#include <bitset>
using namespace std;

int main()
{
	int count=0,n;
	bitset<1000001> prime;

	prime[0]=1;
	prime[1]=1;
	for(int i=2;i<=1000;i++)
		if(prime[i]==0)
			for(int j=i+1;j<=1000000;j++)
				if(j%i==0)
					prime[j]=1;
	
	while(cin>>n)
	{
		for(int i=0;i<=n;i++)
			if(prime[i]==0)
				count++;
		cout<<count<<endl;
		count=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>
#include <bitset>
using namespace std;

int main()
{
	int count=0,n;
	bitset<1000001> prime;

	prime[0]=1;
	prime[1]=1;
	for(int i=2;i<=1000;i++)
		if(prime[i]==0)
			for(int j=i+1;j<=1000000;j++)
				if(j%i==0)
					prime[j]=1;
	
	while(cin>>n)
	{
		for(int i=0;i<=n;i++)
			if(prime[i]==0)
				count++;
		cout<<count<<endl;
		count=0;
	}
		
}
```