#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int phi(int n)
{
    int d=2,p,r=1;
    while (n!=1)
    {
        if (n%d==0)
        {
            p=1;
            while (n%d==0)
            {
                n=n/d;
                p=p*d;
            }
            r=r*(d-1) * (p/d);

        }
    d=d+1;
    }

    return r;
}
int main()
{
    int n,i,s=0;
    fin >> n;

    for (i=2;i<=n;i++)
    {
        s=s+phi(i);
    }
    fout << 1+2*s;
    return 0;
}