#include <fstream>
#include <iostream>

using namespace std;

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



int main() {
	int phi[100000];
	int x, sum = 1;
	fin >> x;

	for (int k = 1; k <= x; ++k) {

		for (int i = 1; i <= x; ++i)
			phi[i] = i - 1;

		for (int i = 2; i <= x; ++i)
			for (int j = 2 * i; j <= x; j += i)
				phi[j] -= phi[i];

		sum += 2 * phi[k];
	}
	
	fout << sum;
	return 0;
}