# include <stdio.h>
long int i,j,n,k,l,a[5000];
int main ()
{
freopen ("fractii.in","r",stdin);
freopen ("fractii.out","w",stdout);
scanf ("%li",&n);
for (i=2;i<=n;i++)
{
for (l=0;l<=n;l++)
a[l]=0;
for (j=2;j<=n;j++)
if (i%j==0)
for (l=j;l<=n;l=l+j)
a[l]=1;
for (l=1;l<=n;l++)
if (a[l]==0)
k++;
}
k=k+n;
printf ("%ld",k);
return 0;   
}