#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <iostream>
#include <cstdlib>
#include<fstream>
#define dim 1000000
using namespace std;

ifstream f("/home/cata/te/src/fractii.in");
ofstream g("/home/cata/te/src/fractii.out");

int fi(int n)
     {
       int result = n,i;
       for( i=2;i*i <= n;i++)
       {
         if (n % i == 0) result -= result / i;
         while (n % i == 0) n /= i;
       }
       if (n > 1) result -= result / n;
       return result;
     }


int main(int argc, char *argv[])
{
long long n, b,a,k=0;float nr;

f>>n;
for(b=2;b<=n;b++)
k=k+fi(b);

// k=k+2*nr;
g<<2*k+1;
f.close();
g.close();

  return EXIT_SUCCESS;
}