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

int main(){
	int n[1000000]={0};
	int x, ans=0;
	
	for(int i=1; i<=999999; i++){
		if(i==1) n[i]=-1;
		else if(n[i]==0){
			for(int k=2; k*i<=999999; k++){
				n[k*i]=-1;
			}
		}
	}
	
	while(cin>>x){
		ans=x;
		for(int j=1; j<=x; j++) ans+=n[j];
		cout << ans << 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>
#include<cstdio>
using namespace std;

int main(){
	int n[1000000]={0};
	int x, ans=0;
	
	for(int i=1; i<=999999; i++){
		if(i==1) n[i]=-1;
		else if(n[i]==0){
			for(int k=2; k*i<=999999; k++){
				n[k*i]=-1;
			}
		}
	}
	
	while(cin>>x){
		ans=x;
		for(int j=1; j<=x; j++) ans+=n[j];
		cout << ans << endl;
	}
	
	return 0;
}
```