#include <fstream>

using namespace std;

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

int euler (int n)
{
   int d=2,p=n;
   while (d*d<n)
   {
      if (n%d==0)
          {
             p=p*(d-1)/d;
             while (n%d==0)
             {
                n=n/d;
             }
          }
          d++;
   }
   if (n>1)
   {
     p=p*(n-1)/n;
   }
   return p;
}
int main()
{
    int n,i,s=0;
    in>>n;
    for (i=1;i<=n;i++)
    {
       s=s+euler(i);
    }
    out<<s;
    return 0;
}