#include <iostream>
#include <fstream>
#include <bits/stdc++.h>

using namespace std;

ifstream f("fractii.in");
ofstream g("fractii.out");

int main()
{
    int n,k;
    f>>n;
    int ct=0;
    for(k = 1; k <= n; k++)
    {
        int fractii = k;
        int aux=k;
        for (int p = 2; p * p <= aux; p++)
        {
            if (aux % p == 0)
            {
                while (aux % p == 0)
                    aux /= p;
                fractii-= fractii / p;
            }
        }
        if (aux > 1)
            fractii-= fractii / aux;
        ct+=fractii;
    }
    g << ct*2-1;
}