#include <iostream>
using namespace std;

int main(){
	int n;
	static bool c[1000000]={true};
	static int t[1000000];t[0] = 0;
	for(int i = 2;i < 1000000;i++){
		for(int j = 2;i*j < 1000000;j++){
			c[i*j] = true;
		}
		t[i]=t[i-1]+!c[i];
	}
	for(int n;cin>>n;n++){
		cout << t[n] << endl;
	}
	return 0;
}
### Prompt

Your challenge is to write 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 <iostream>
using namespace std;

int main(){
	int n;
	static bool c[1000000]={true};
	static int t[1000000];t[0] = 0;
	for(int i = 2;i < 1000000;i++){
		for(int j = 2;i*j < 1000000;j++){
			c[i*j] = true;
		}
		t[i]=t[i-1]+!c[i];
	}
	for(int n;cin>>n;n++){
		cout << t[n] << endl;
	}
	return 0;
}
```