let ap : all 'a 'b. ('a -> 'b) -> 'a -> 'b =
  fun 'a 'b ->
    fun f: ('a -> 'b) ->
      fun x: 'a ->
        f x

let inc : int -> int =
  fun y: int -> ap[int,int] (fun z: int -> z + 1) y

in print[int] (inc 5)