#include<fstream.h>
long long  q=0,aux,i,j,n,k;
int main()
{ifstream f("fractii.in");ofstream g("fractii.out");f>>n;
for(i=2;i<=n;i++)
{aux=i;j=2;k=0;
while(aux!=1)
{if(aux%j==0)
 {k=k+n/j;
 while(aux%j==0) aux/=j;}
 j++;}
 q=q+n-k;}
 q=q+n;
 g<<q;
return 0;}