# Party acquaintances

**Discrete Mathematics**Level 4

(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.