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

const int MAX = 1e6;

int vect[MAX + 1];
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    int i, n;
    f >> n;
    vect[1] = 1;
    for (i = 2; i <= n; i++)
    {
        vect[i]--;
        for (int j = 2 * i; j <= n; j += i)
            vect[j] -= vect[i];
    }
    long long ans = 0;
    for (i = 1; i <= n; i++)
        ans += 1LL * vect[i] * (n / i) * (n / i);
    g << ans;
}