There are n people who can shake hands with one another (where n> 1). Use pigeonhole principle to show that there is always apair of people who will shake hands with the same number ofpeople.
Hint. Pigeonhole principle does not immediately apply to thisproblem. Solve the problem for two cases:
(1) There is no person who shakes hands with everyone else (allhandshake numbers are strictly less than n ? 1). Easy case.
(2) There is a person who shakes hands with everyone else (hand-shake number is n ? 1). What can you say about handshake numbersfor everyone else?
