#include <fstream>
#include <iostream>
#include <bitset>
#include <cstdio>
#include <cstdlib>
using namespace std;

ifstream in;
ofstream out;

int main(int argc, char *argv[])
{
    in.open("fractii.in");
    out.open("fractii.out");

    int n;
    in >> n;
    int *v = (int*)malloc((n + 1) * sizeof(int));
    long long total = 0;
    for (int i = 2; i <= n ;i++)
        v[i] = i - 1;

    for (int i = 2; i <= n; i++) {
        for (int j = 2 * i; j <= n; j += i) {
            v[j] = v[j] - v[i];
        }
    }

    for (int i = 2; i <= n; i++)
        total += v[i];

    total *= 2;
    ++total;

    out << total << endl;
    free(v);
    
    in.close();
    out.close();
    return 0;
}