#include <iostream>
using namespace std;
int main()
{
    int phi[1000],i,j,s,c,n;
    cin >> n;
    s=0;
    for (i=1; i<=n; i++)
    {
        phi[i]=i-1;
    }
  for (i=2; i<=n; i++)
    {
        for (j=i+i; j<=n; j=j+i)
        {
            phi[j]=phi[j]-phi[i];

        }
    }

    for (i=2; i<=n; i++)
    {
        c=phi[i];
        s=s+c;
    }
    cout <<" "<<s*2+1;
return 0;
}