type Tree =
    | Empty
    | Node of int * Tree * Tree

let rec insert tree v =
    match tree with
    | Node(v0, left, right) when v<v0 -> Node(v0, (insert left v), right)
    | Node(v0, left, right) when v>v0 -> Node(v0, left, (insert right v))
    | Empty -> Node(v, Empty, Empty)

let rec printTree tree =
    match tree with
    | Empty -> ()
    | Node(v, left, right) ->
        printTree left
        printfn "%d" v
        printTree right