#include<iostream>
using namespace std;
bool b[1000005];
int s[1000005];
int main(){
	int i,j,k;
	int n;
	b[i]=true;
	for(i=2;i<1000000;i++){
		if(b[i]==false){
			for(j=2*i;j<1000000;j+=i){
				b[j]=true;
			}
			s[i]=s[i-1]+1;
		}else{
			s[i]=s[i-1];
		}
	}
	while(cin>>n){
		cout<<s[n]<<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;
bool b[1000005];
int s[1000005];
int main(){
	int i,j,k;
	int n;
	b[i]=true;
	for(i=2;i<1000000;i++){
		if(b[i]==false){
			for(j=2*i;j<1000000;j+=i){
				b[j]=true;
			}
			s[i]=s[i-1]+1;
		}else{
			s[i]=s[i-1];
		}
	}
	while(cin>>n){
		cout<<s[n]<<endl;
	}
	return 0;
}
```