[Haskell-beginners] nim

Hi All, In the game of nim I want to make a move such as take x from pile A. This will then be subtracted from the starting list.Is this correct in as much as I want to have a move Take 3 from pile A: input would be A3 I need it to return a list as I wish to take this result and use zipwith (-) [starting list][result]. How do I use the result, do I store in a variable? typeOfMove :: (a,b) -> [Int] typeOfMove ax |ax = [x,0,0] |bx = [0,x,0] |cx = [0,0,x] John