#include <stdio.h>

int cmmdc(int a, int b){

	int r = a % b;
	while (r != 0) {

		a = b; 
		b = r;
		r = a % b;
	}

	return b;
}

int main(){

	freopen("fractii.in", "r", stdin);
	freopen("fractii.out", "w", stdout);

	int n, p, q, s = 0;

	scanf ("%d", &n);

	for (p = 1; p <= n; p++) {

		for (q = p + 1; q <= n; q++) {

			if (cmmdc(p, q) == 1) {

				s ++; 
			}
		}
	}

	printf("%d\n", s * 2 + 1);

	return 0;
 }