/*http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0009&lang=jp*/

#include <iostream>

using namespace std;

int main()
{
    int n;

    while (cin>>n){
        int count=0;

        while (1 < n){
            int prime_flag=1;
            for (int j = n - 1; prime_flag && 1 < j; j--) {
                if(n % j==0){
                    prime_flag=0;
                }
            }
            count+=prime_flag;
            n--;
        }
        cout<<count<<endl;
    }
    return 0;
}