#include <stdio.h>

int prime(int nr1,int nr2){
 int div,j;
 for(div=2;div<=nr2;div+=2){
 if((nr1%div==0)&&(nr2%div==0))return 0;                          
 }
 return 1;
}

int main(){
  int i,j,N,numar=0,a;
  freopen("fractii.in","r",stdin);
  freopen("fractii.out","w",stdout);
  scanf("%d",&N);
  numar=N;
  
  for(i=3;i<=N;i++){
    for(j=2;j<i;j++)
      {//if((i&1)||(j&1))
                     if(prime(i,j)){
                        //printf("%d si %d sunt prime!",i,j);
                        numar++;
                      }
         
      }
   } 
   printf("%d\n",2*numar-1);
  return 0;
  }