open System

type Rectangle = {Length: int; Width: int}
type Square = {Length:int}
type Circle = {Radius: float}
type Shape = Rectangle of float * float | Square of float | Circle of float
let areaof shape =
    match shape with
    | Rectangle (x, y)  -> x * y
    | Square x -> x * x
    | Circle radius -> 3.14 * radius * radius
    | _ -> failwith "Undefined shape"

let rect = Rectangle(3.0,4.0)
let circle = Circle(51.0)
let square = Square(13.0)
let rectArea = areaof rect
let squareArea = areaof square
let circleArea = areaof circle