totient

#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>
#include <cmath>
#include <math.h>
#include <queue>
#include <string>

using namespace std;

ifstream fin("fractii.in");
ofstream fout("fractii.out");

double phi(int n)
{
    double rez = n;
    for (int i = 2; i*i <= n; i++)
    {
        if (n%i == 0) {
            while (n%i == 0) n /= i;
            rez = rez * (1.0 - (1.0 / (double)i));
        }
    }
    if (n > 1)
        rez = rez * (1.0 - (1.0 / (double)n));

    return rez;
}

int main()
{
    ios_base::sync_with_stdio(false);
    int n;
    long long total = 0;
    fin >> n;
    total = 0;
    for (int i = 1; i <= n; i++)
        total += round(phi(i));
    fout << total*2 - 1;
}