#include <iostream>
#include <fstream>

using namespace std;

ifstream f("fractii.in");
ofstream g("fractii.out");

int eprim(int x){
    int d=0;
    for (int div=2; div<= x/2; div++){
        if (x%div == 0) d++;
    }
    if (d==2) return 1;
    return 0;
}

int main()
{   int N,fr;
    fr=0;
    f>>N;
    for (int i=1; i<= N; i++){
        for (int j=1; j<=N; j++){
            if (eprim(i)==1 || eprim(j)==1) fr++;
        }
    }
    g<<fr;
    return 0;
}