#include <iostream>
#include <fstream>
using namespace std;

int primes[1000001];

bool isPrime(int n)
{
    for (int i = 2; i*i <= n; i++) {
        if (n % i == 0) {
            return false;
        }
    }

    return true;
}

int calculatePrimes(int n)
{
    int primeCount = 0;
    for (int i = 2; i <= n; i++) {
        if (isPrime(i)) {
            primes[primeCount++] = i;
        }
    }

    return primeCount;
}

int phi(int n, int primeCount)
{
    int value = n;
    for (int i = 0; primes[i] <= n && i < primeCount; i++) {
        if (n % primes[i] == 0) {
            value = value * (primes[i] - 1) / primes[i];
        }
    }

    return value;
}

int main()
{
    ifstream input("fractii.in");
    ofstream output("fractii.out");
    int n = 0;

    while (input >> n) {
        int primeCount = calculatePrimes(n);

        int sum = 0;
        for (int i = 2; i <= n; i++) {
            sum += phi(i, primeCount);
        }

        output << sum * 2 + 1 << endl;
    }

    return 0;
}