open System

[<EntryPoint>]
let main argv =
    let a = stdin.ReadLine().ToCharArray()
    let b k = Char.IsUpper(k)
    let acase k = 
        match k with
        | true -> printfn "A"
        | false -> printfn "a"
        | _ -> printfn "non char"

    a.[0] |> b |> acase
    
    0 
