#include<fstream>
using namespace std;
long n,k=0,c[1000],i,j;
int main() 
{ 
     ifstream f("fractii.in"); 
     ofstream g("fractii.out"); 
    f>>n; 
     f.close();
     for(i=2;i<=n;i++) 
    c[i]=i-1; 
   for(i=2;i<=n;i++) 
{ 
   k=k+c[i]; 
  for(j=i*2;j<=n;j=j+i) 
   c[j]=c[j]-c[i]; 
} 
  if(k=k*2+1)
   g<<k<<" "; 
  return 0;
 }