#include<fstream>
bool cmmdc(unsigned i, unsigned j)
{
	if (!i)return j == 1;
	if (!j)return i == 1;
	return cmmdc(j, i%j);
}
int 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 = 2 * i; k <= n;)a[k += i] = 0;;
		for (unsigned j = i + 1; j <= n; j++)
			nr += 2 * (a[j] && cmmdc(i, j));
		for (unsigned k = 2 * i; k <= n;)a[k += i] = 1;;
	}
		g << 2 * n + nr - 1;
		g.close();
}