A group of 5 people want to keep their secret document in a safe. They want to make sure that in the future, only a majority (>=3) of people can open the safe. To accomplish this they want to put some locks on the safe, whereby each of the locks have to be opened to access the safe. Each lock can have multiple keys; but each key only opens one lock. How many locks are required at minimum? How many keys will each member carry?