#include <iostream>
#include <fstream>
using namespace std;

ifstream f;
ofstream g;

long int i,n,j,s,k;

main()
{

f.open("fractii.in");
g.open("fractii.out");

f>>n;
s=0;
k=0;
for(i=2;i<=n;i++){
                 k=0;
                 j=2;
                 if(i>j){while(i%j!=0)j++;s=s+n-n/j-n/i/j;}
                 else   {while(j%i!=0)j++;
                 s=s+n-n/j-n/j/i;}

                 }



g<<s+n+1;
g.close();
}