#include <stdio.h>

#define TRUE 1
#define FALSE 0

typedef int Boolean;

Boolean is_good(int n)
{
    int divisor;

    if (n <= 1)
    {
        return FALSE;
    }
    for (divisor = 2; divisor * divisor <= n; divisor++)
    {
        if (n % divisor == 0)
        {
            return FALSE;
        }
    }
    return TRUE;
}

int main(void)
{
    int n;

    printf("Enter a number: ");
    scanf("%d", &n);
    if (is_good(n))
    {
        printf("Good!\n");
    }
    else
    {
        printf("Not good.\n");
    }

    return 0;
}