#include <stdio.h>
#include <math.h>
FILE *f;
  
   
int n;   


int main(void){
	int a,i,j;
	f=fopen("fractii.in","r");
	fscanf(f,"%d",&n);
	fclose(f);
	
	int s=0;
	s+=n;
	for (a=1;a<=n;a++){
		for(i=2;i<=a/2;i++){
			
			if (a%i!= 0){
				s+=1;
				
			}
			else{}
			
		}
		if (a>=3){
		for(i=a/2+1;i<a;i++){
			s+=1;
		}
		}
    }
    int sf;
    sf=(s-1)*2+1;
    f=fopen("fractii.out","w");
    fprintf(f,"%d",sf);
    fclose(f);
    
}