#include<stdio.h>
FILE*f=fopen("fractii.in","r");
FILE*g=fopen("fractii.out","w");
int v[1000002],j,i,nr,n;
int main () {
	fscanf(f,"%d",&n);
	nr=n;
	for(i=2;i<=n;i++){
		nr+=n;
		for(j=1;j<=n;j+=i)
			nr--;
	}
	fprintf(g,"%d",nr);
	
	fclose(f);
	fclose(g);
	return 0;
}