Wow! This problem is kind of tricky. If you're ready to put your thinking cap on, brace yourself, and good luck! Otherwise, you can skip it for now and return any time later.
Suppose there are people who want to sit around a circular table. How many different ways can the people be seated?
Hint: It only matters how the people sit relative to each other. In other words, rotations of a seating are considered to be the same arrangement.