#include<fstream>
bool cmmdc(unsigned i, unsigned j)
{
	if (!i)return j == 1;
	if (!j)return i == 1;
	return cmmdc(j, i%j);
}
void main()
{
	unsigned n, nr = 0, a[1000000] = {};
	std::ifstream f("fractii.in");
	std::ofstream g("fractii.out");
	f >> n;
	f.close();
	for (unsigned i = 2; i < n; i++)
	{
        for (unsigned k = i * 2; k <= n; a[k += i] = 1);
		for (unsigned j = i + 2; j <= n; j++)
			nr += 2 * (!a[j] && cmmdc(i, j));
		for (unsigned k = i * 2; k <= n; a[k += i] = 0);
	}
	g << nr - 1 + (n - 1) * 4;
	g.close();
}