#include <fstream>
#include <iostream>
#define nmax 1000001
using namespace std;

ifstream f("fractii.in");
ofstream g("fractii.out");

int v[nmax];

int main()
{
    int n;
    long long s = 0;
    f >> n;
    v[1] = 1;
    for (int i = 2; i <= n; i++)
    {
        v[i] = i - 1;
    }
    for (int i = 2; i <= n; i++)
    {
        s += v[i];
        for (int j = 2 * i; j <= n; j += i)
        {
            v[j] -= v[i];
        }
    }

    g << 2 * s + 1;

    return 0;
}