#include <iostream>
#include <fstream>

std::ifstream fin ("fractii.in");
std::ofstream fout ("fractii.out");

const int MaxN = 1000001;
int n, a[MaxN];

int main ()
{
    fin >> n;

    for (int i = 2; i <= n; ++i)
        a[i] = i - 1;

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

    long long sum = 0;

    for (int i = 2; i <= n; ++i)
        sum += a[i];

    fout << 2 * sum + 1;
}