Turn a "Y" or "N" answer into a number

I want to have a cell where the user puts in a Y or N answer but have a formula see it as a 1 or a 0. Three columns will be yes or No answers then the final column will add them up and give a score. How do I allow a person to put in a Y or N and still have my formula assign a "1" or "0" to the answer then add them up? Thanks hope Im clear.