#include<stdio.h>
FILE *f=fopen("fractii.in","r"),*g=fopen("fractii.out","w");
int i,p,j,k;
int n,a[1000000],sum;
int tot(int x)
{
	long s=1;
	for( j=2;j<=n;j++)
	{ if(x%j==0||j%x==0)
		for( k=j;k<=n;k+=j) a[k]=1;
	 s+=a[j];
	} 
	return s;
}
int main()
{
	fscanf(f,"%d",&n);
	fclose(f);
	sum=n;
	for(i=2;i<=n;i++) sum=sum+tot(i);
	fprintf(g,"%d",sum);
	fclose(g);
	return 0;
}