# include <fstream>
# include <cstring>
# include <cmath>
using namespace std;

int fi(int n)
     {
       int result = n;
       for(int 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 n ;
long long nr  = 0;
fscanf ( fopen ( "fractii.in", "r" ) , "%d", &n ) ;
    for (int i=2;i<=n;i++)
      nr += fi ( i ) ;
    fprintf ( fopen ( "fractii.out", "w" ), "%lld", nr * 2 + 1 ) ;
    return 0;
}