#include <iostream>
#include <fstream>
using namespace std;

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

int main()
{
    int n,total,i,j;
    f>>n;
    total=n;
    for(i=2;i<=n;i++){
        for(j=2;j<=n;j++){
            if(i%j!=0){
                    total=total+1;
            }
        }
    }
    g<<total;
    f.close();
    g.close();
    return 0;
}