#include <stdio.h>
int main(void)
{ freopen("fractii.in","r",stdin);
freopen("fractii.out","w",stdout);
 int n,s,t;
 scanf("%d",&n);
 s=0;
 for (int i=1; i<=n; ++i)
{	 
	if (n%i==0) s=s+n/i-1; 
} 
 t=n*n-s;
 printf("%d",t);
 return 0;
}