#include <iostream>


int main()
{
  long i,j,n,s,t[1000010];
  FILE *f;

f=fopen("fractii.in","r");
fscanf(f,"%ld",&n);
fclose(f);
           
   for(i=0;i<=n;i++)t[i]=i-1;
   
   for(i=2;i<=n;i++)
    for(j=i*2;j<=n;j+=i)
       t[j]-=t[i];
       
   s=0;    
   for(i=2;i<=n;i++)s+=t[i];
   
f=fopen("fractii.out","w");
fprintf(f,"%ld",s*2+1);
fclose(f);

return(0);

}