#include <fstream>
#define L 1000000
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
int i,n,v[L],t,s,j;
int main()
{
    f>>n;

    for(i=1;i<=n;++i) v[i]=n;

    for(i=2;i<=n;++i,t=0) if (v[i]==n)
    {
      for(j=i;j<=n;j+=i,t++);
       for(j=i;j<=n;j+=i) v[j]-=t;
    }

   for(i=1;i<=n;++i) s+=v[i];
   g<<s;


   f.close();
   g.close();
    return 0;
}