(i) Each pair of people who are mutually acquainted has exactly 4 common acquaintances.
(ii) Each pair of people who are mutually unacquainted has exactly 2 common acquaintances
Find the number of possible values of \( n \).
Note: If you think that there are infinitely many answers, then input your answer as 999. If you think that there are no answers, input your answer as 0.