#include <stdio.h>

#define MAX 10010

int p[MAX];
int n;

void Erastostene()
{
    int i, j;

    for(i = 1; i <= n; i++) p[i] = 1;

    for(i = 2; i <= n; i++)
	if(p[i])
	    for(j = i + i; j <= n; j += i)
		p[j] = 0;
}

int Tot(int l)
{
    int i,a;
    float t;

    if (p[l]) t = l - 1;
    else
    {
	t = l;
	i = 2;
	while(l != 1)
	{
	    while(p[i] == 0 || l % i != 0) i++;
	    while(l % i == 0) l /= i;

	    t = t * (1 - 1/(float)i);
	}
    }
    a = (int) t;
    return(a);
}

int main()
{
    FILE *f;
    long long r = 0;
    int i;

    f = fopen("fractii.in", "rt");
    fscanf(f, "%d", &n);
    fclose(f);

    Erastostene();

    for(i = 1; i <= n; i++) r = r + Tot(i);

    r = 2 * r + 1;

    f = fopen("fractii.out", "wt");
    fprintf(f, "%li", r);
    fclose(f);
 return(0);
}