Question 83
Given a prime number $p$, a set is said to be *p-good* if the set contains exactly three elements $a, b, c$ and $a + b \equiv c \pmod p$.
Find all prime number $p$ such that $\{1, 2, \dots, p-1\}$ can be partitioned into several $p$-good sets.
Find all prime number $p$ such that $\{1, 2, \dots, p-1\}$ can be partitioned into several $p$-good sets.