#include <iostream>
using namespace std;

int main(){
  int a,m[1000000],cou=1,j;
  m[1]=0;
  m[2]=1;
  for(int i=3;i<1000000;i++){
    if(i%2==0){
      m[i]=cou;
      continue;
    }
    for(j=3;j*j<=i;j+=2)if(i%j==0)break;
    if(j*j>i)cou++;
    m[i]=cou;
  }
  while(cin>>a){
    cout << m[a]<<endl;
  }
  
 
  return 0;
}
  
### Prompt

In CPP, your task is to solve 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 a,m[1000000],cou=1,j;
  m[1]=0;
  m[2]=1;
  for(int i=3;i<1000000;i++){
    if(i%2==0){
      m[i]=cou;
      continue;
    }
    for(j=3;j*j<=i;j+=2)if(i%j==0)break;
    if(j*j>i)cou++;
    m[i]=cou;
  }
  while(cin>>a){
    cout << m[a]<<endl;
  }
  
 
  return 0;
}
  
```