#include <fstream>
using namespace std;
ifstream f ("fractii.in");
ofstream g ("fractii.out");
int N, i, j;
long long fr;
int main ()
{
    f>>N;
    //i=impar
    for (i=3; i<N; i=i+2)
        for (j=i+1; j<=N; j++)
        {   if(j%i)
           {

            int a=i;
            int b=j;
            int r=a%b;
            while (r)
                {
                    a=b;b=r;r=a%b;
                }
            if (b==1)
                fr++;}
        }
        //i==par
        for (i=4; i<N; i=i+2)
        for (j=i+1; j<=N; j=j+2)
        {   if(j%i)
           {

            int a=i;
            int b=j;
            int r=a%b;
            while (r)
                {
                    a=b;b=r;r=a%b;
                }
            if (b==1)
                fr++;
              }
        }
    g<<fr*2+2*N-1+(N-1)/2*2;
    f.close ();
    g.close ();
    return 0;
}