#include<stdio.h>
#include<math.h>
FILE *f=fopen("fractii.in","r"),*g=fopen("fractii.out","w");
unsigned long i,j,n,nr;
int main()
{
fscanf(f,"%ld",&n);
fclose(f);
for(i=2;i<=n;i++)
        {
        nr++;
        for(j=2;j<=i-1;j++)
                {
                if(i%j!=0)
                        nr++;
                }
        }
fprintf(g,"%ld",nr*2+1);
fclose(g);
return 0;
}