#include <fstream.h>  
    long v[1000001];  
    long n;  
     
  void fract ()  
   {  
      long i,j;  
             
        for ( i = 1; i <= n; ++i)  
    v[i] = i-1;  
for ( i = 2; i <= n; ++i)  
    for ( j = 2*i; j <= n; j += i)  
        v[j] -= v[i];  
     }  
          
     int main ()  
  {   
    long long k=0,h;  
    long i;  
     fstream f("fractii.in",ios::in);  
   fstream g("fractii.out",ios::out);  
 f>>n;  
     fract();  
    for(i=2;i<=n;i++)  
      {  
        k=k+v[i];  
        }   
     h=2*k+1;  
    g<<h;  
    return 0;  
    }