#include<fstream.h>
#define dim 1000000
long n,v[dim],w[13],max;

int main()
{ifstream f("fractii.in");
f>>n;
f.close();
long i,j,k,t;
k=n/2;
for(i=1;i<=n;++i)v[i]=i-1;
for(i=2;i<=k;i++)
 for(j=2*i;j<=n;j+=i)
  v[j]-=v[i];
for(i=1;i<=n;++i)
 {t=2*v[i];
  k=0;w[k]+=t;
  while(w[k]>9)
   {w[k+1]+=w[k]/10;
    w[k]=w[k]%10;
    ++k;
   }
  if(k>max)max=k;
 }
ofstream g("fractii.out");
++w[0];
for(i=max;i>=0;--i)
 g<<w[i];
g<<'\n';
g.close();
return 0;
}