#include<stdio.h>
#pragma warning(disable:4996)
using namespace std;

int gcd(int a, int b) {
	int r;
	r = a % b;
	while (r) {
		a = b;
		b = r;
		r = a % b;
	}
	return b;
}

int main() {
	freopen("fractii.in", "r", stdin);
	freopen("fractii.out", "w", stdout);
	int i, j, n, count = 0;

	scanf("%d", &n);

	for (i = 1; i <= n; i++)
		for (j = 1; j <= n/2; j++)
			if (gcd(i, j) == 1)
				count++;
	
	printf("%d", count*2);

	return 0;
}