#include <iostream>
#include <fstream>
using namespace std;
long long sol;
int rez[1000003], n;
int main ()
{
    ifstream cin ("fractii.in");
    ofstream cout ("fractii.out");
    cin >> n;
    for (int i = 1; i <= n; i++)
        rez[i] = i - 1;
    for (int i = 2; i <= n; i++)
    {
        for (int  j = 2 * i ; j <= n; j += i)
            rez[j] -= rez[i];
        sol = (long long) sol +  rez[i];
    }
    cout << 2 * sol + 1;
    return 0;
}