#include <bits/stdc++.h>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long n, i, j, a, k, nmax, s;

long long indicator(long long n)
{
    if(n == 0)
        return 0;
    long long rez = 1, d = 3, put = 0;
    while(n % 2 == 0)
    {
        put++;
        n /= 2;
    }
    if(put > 0)
        rez *= (2 - 1) * pow(2, put - 1);
    while(d * d <= n)
    {
        put = 0;
        while(n % d == 0)
        {
            put++;
            n /= d;
        }
        if(put > 0)
            rez *= (d - 1) * pow(d, put - 1);
        d += 2;
    }
    if(n > 1)
        rez *= (n - 1);
    return rez;
}

int main()
{
    f >> n;
    for(i = 1; i <= n; i++)
        s += indicator(i);
    g << (s * 2 - 1);
    return 0;
}