In a survey of 80 households, it was found that: 30 had at least one dog, 42 had at least one cat, 21 had at least one "other" pet (fish, turtle, reptile, hamster, etc.), 20 had dog(s) and cats), 10 had cats) and "other" pet(s), 8 had dog(s) and "other" pet(s) and 5 had all three types of pets. How many "other" pets) owners also have dog(s) or cats) but not both