#include<bits/stdc++.h>
using namespace std;

int main(){
	int a[1000000]{};
	bool b[1000000]{};
	a[1]=0;
	int s=0;
	for(int c=2;c<1000000;c++){
		if(b[c]==false){
			s++;
			for(int d=c*2;d<1000000;d+=c)b[d]=true;
		}
		a[c]=s;
	}
	int k;
	while(cin>>k){
	printf("%d\n",a[k]);	
	}}
### 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<bits/stdc++.h>
using namespace std;

int main(){
	int a[1000000]{};
	bool b[1000000]{};
	a[1]=0;
	int s=0;
	for(int c=2;c<1000000;c++){
		if(b[c]==false){
			s++;
			for(int d=c*2;d<1000000;d+=c)b[d]=true;
		}
		a[c]=s;
	}
	int k;
	while(cin>>k){
	printf("%d\n",a[k]);	
	}}
```