//
//  Fractii.cpp
//  
//
//  Created by Raoul Bocancea on 23/11/2018.
//

#include <fstream>

const std :: string programName = "fractii";
std :: ifstream f(programName + ".in");
std :: ofstream g(programName + ".out");

int main(void) {
    int N;
    f >> N;
    int v[N];
    for (int i = 1; i <= N; ++i)
        v[i] = i - 1;
    for (int i = 2; i <= N; ++i)
        for (int j = 2 * i; j <= N; j += i)
            v[j] -= v[i];
    int64_t s(0);
    for (int i = 2; i <= N; ++i)
        s += v[i];
    g << 2 * s + 1;
    return 0x0;
}