/*#include<stdio.h>
#include<stdlib.h>
long n,phi[1000002];
int main()
  {int i,j,s=0;
   //freopen("fractii.in","rt",stdin);
   //freopen("fractii.out","wt",stdout);
   scanf("%d",&n);
   for(i=1;i<=n;++i) phi[i]=i-1;
   for(i=1;i<=n;++i)
      {for(j=2*i;j<=n;j+=i)
           phi[j]-=phi[i];
       s+=phi[i];
      }
   for(i=1;i<=n;++i) printf("%d ",phi[i]); printf("\n");
   printf("%d\n",2*s+1);
   system("PAUSE");
   return 0;
  }*/
    #include<fstream.h>
    #include<stdlib.h>
    #define MAX 1000001
    //#define f cin
    //#define g cout
    //using namespace std;

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

   long a[MAX],n,s,i,j;

   main()
   {     f>>n;
         f.close();
         for(i=1;i<=n;i++)
         a[i]=i-1;
         for(i=1;i<=n;i++)
         {
            for(j=2*i;j<=n;j=j+i)
            a[j]-=a[i];
            s+=a[i];
            }
         g<<2*s+1;
         //system("PAUSE");
         g.close();
   }