#include<stdio.h>
FILE *f=fopen("fractii.in","r");
FILE *g=fopen("fractii.out","w");
main()
{
long n,i,j,s;
fscanf(f,"%ld",&n);
for(i=1;i<=n;i++)
{
int k=0;
for(j=1;j<i;j+=i)
k++;
s=s+k;
}
fprintf(g,"%ld",s);
return 0;
}