open System 

type Explicit =          
    static member inline ($) (_:int32, _:Explicit) = int
    static member inline ($) (_:int64, _:Explicit) = int64

let inline convert (value:'a): 'b = 
    (Unchecked.defaultof<'b> $ Unchecked.defaultof<Explicit>) value

let inline fromInt (x: int): 'a = convert x

module NumericLiteralG =
    let inline FromZero(): ^a = LanguagePrimitives.GenericZero
    let inline FromOne(): ^a = LanguagePrimitives.GenericOne
    let inline FromInt32 n = fromInt n

let R() = Console.ReadLine()

let f (x: float): float =
    pown (x / 3.) 3

let L = R() |> float

f L 
|> printfn "%f" 