#include <stdio.h>
#include <string.h>
#include <math.h>
long long ok[10000];
int main(){
	long long n,i,s=1,j,k;
	memset(ok,0,sizeof(ok));
	FILE*f=fopen("fractii.in", "r");
	FILE*g=fopen("fractii.out", "w");
	fscanf(f,"%lld",&n);
	for(i=1;i<=n;i++){
		for(j=1;j<=i;j++){
			if(i%j==0&&j!=1){
				k=1;
				while(k<=i){
                                        ok[k*j]=1;
					k++;
				}
			}
			if(!ok[j])
				s+=2;
		}
                memset(ok,0,sizeof(ok));
	}
	fprintf(g,"%lld",s-2);
	fclose(f);
	fclose(g);
	return 0;

}