#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

unsigned int cmmdc(unsigned int a, unsigned int b)
{
	if (b)
		return cmmdc(b, a % b);
	else
		return a;
}

unsigned int bk(int N)
{
	int sum = 0;
	for (int i = 1; i <= N; i++)
		for (int j=i; j<=N; j++)
			if (cmmdc(i, j)==1)
				sum++;

	return sum;
}

int main()
{
	FILE* f = fopen("fractii.in", "rt");
	int N;

	fscanf(f, "%d", &N);

	f = fopen("fractii.out", "wt");

	fprintf(f, "%d\n", 2*bk(N) - 1);
	fflush(stdout);
	fclose(f);
	return 0;
}