Find a prime number $p$ and an integer $b<p$ such that $p$ divides $b^{p−1}−1$.

Question

Find a prime number $p$ and an integer $b<p$ such that $p$ divides $b^{p−1}−1$.

First I think of long divisions but it didn't work out. Now I'm stuck..

Answer 1

Hint; You can Make $p=3$ and $b=2$.