#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
int main()
{
    int n,cont=0,i,j;
    in>>n;
    cont=n;
    cont=cont+n-1;
    for(i=2;i<=n;i++)
    {
          for(j=2;j<=n;j++ && j!=i)
          {
                    if(j%i!=0) cont++;
          }
    }
    out<<cont-1;
    return 0;
}