#include<fstream>
#include<math.h>

using namespace std;
ifstream fin ("fractii.in");
ofstream fout ("fractii.out");

int main ()
{
    long long k,s,i;
    fin>>k;
  long long  phi[k];
   /*l=2;
    nr=0; 
    for(i=1;i<=k-1;i++)
 for(w=i+1;w<=k;w++)
   {
                     n=i;
                     m=w;
                   // if(i%2!=0 && w%2==0 || i%2==0 && w%2!=0 || i%2!=0 && w%2!=0)
 //   {
                                while(n%m)
    {            a=n%m;
                 n=m;
                 m=a;
                  x=n%m; 
                 }
                 if(m==1)
                nr++;}
                //    }
                 fout<<nr*2+1;*/
                 for (int i = 1; i <=k; ++i)
                 phi[i] = i-1;
                    for (int i = 2; i <=k; ++i)
                               for (int j = 2*i; j <=k; j += i)
        phi[j] -= phi[i];
        s=0;
        for(i=1;i<=k;i++)
        s+=phi[i];
       // for(i=1;i<=k;i++)
       // fout<<phi[i]<<" ";
        fout<<(2*s)+1;
return 0;

}