#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long n;
long long cmmdc (long long a, long long b) {
    while (a != b) {
        if (a > b) {
            a = a - b;
        } else {
            b = b - a;
        }
    }
    long long r = a;
    return r;
}

int main () {
    int nr = 1;
    cin >> n;
    for (int i = 1; i < n; i++) {
        for (int j = i + 1; j <= n; j++) {
            if (cmmdc(i, j) == 1) {
                nr = nr + 2;
            }
        }
    }
    g << nr;
}