#include <fstream>
using namespace std;

long long phi(long long n) {
    long long result = n;
    for (long long i = 2; i * i <= n; i++) {
        if (n % i == 0) {
            while (n % i == 0)
                n /= i;
            result -= result / i;
        }
    }
    if (n > 1)
        result -= result / n;
    return result;
}

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

    int n;
    fin >> n;

    long long count = 0;
    for (int i = 1; i <= n; i++) {
        count += phi(i);
    }

    fout << count << '\n';

    return 0;
}