Chef and his Magic Show

Problem Statement: Chef is hosting a magic show. He prepares a trick to amaze audience where he places K coins on table where K is always even, out of which half are facing heads up and and other half tails up.There are N people in the audience and chef asks N-1 people to come one by one and flip exactly any one of the coins.The last person from the audience (Nth person) is asked to hide any one