#include<stdio.h>


int main(){
	int n;
	bool data[1000000];

	int i,j;
	data[0]=data[1]=0;
	for(i=2;i<1000000;i++){
		data[i]=1;
	}

	for(i=0;i<1000000;i++){
		if(data[i]==1){
			for(j=i+i;j<1000000;j=j+i){
				data[j]=0;
			}
		}
	}


	while(scanf("%d",&n)!=EOF){
		j=0;
		for(i=0;i<n+1;i++){
			if(data[i]==1)j++;
		}
		printf("%d\n",j);
	
	}
	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<stdio.h>


int main(){
	int n;
	bool data[1000000];

	int i,j;
	data[0]=data[1]=0;
	for(i=2;i<1000000;i++){
		data[i]=1;
	}

	for(i=0;i<1000000;i++){
		if(data[i]==1){
			for(j=i+i;j<1000000;j=j+i){
				data[j]=0;
			}
		}
	}


	while(scanf("%d",&n)!=EOF){
		j=0;
		for(i=0;i<n+1;i++){
			if(data[i]==1)j++;
		}
		printf("%d\n",j);
	
	}
	return 0;
}
```