#include<iostream>
#define Number 1000000
using namespace std;
int main(){
  int n;
  int table[Number]={0};
  for(int i=2;i<Number;i++){
    if(table[i]==0){
      for(int j=2*i;j<Number;j+=i){
	table[j]=1;
      }
    }
    table[i]=(table[i]?0:1)+table[i-1];
  }
  while(cin>>n){
    cout<<table[n]<<endl;
  }
  return 0;
}
### 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<iostream>
#define Number 1000000
using namespace std;
int main(){
  int n;
  int table[Number]={0};
  for(int i=2;i<Number;i++){
    if(table[i]==0){
      for(int j=2*i;j<Number;j+=i){
	table[j]=1;
      }
    }
    table[i]=(table[i]?0:1)+table[i-1];
  }
  while(cin>>n){
    cout<<table[n]<<endl;
  }
  return 0;
}
```