Fibb

open System
 
(* This is a
multi-line comment *)
 
// This is a single-line comment
 
let rec fib = function
    | 0 -> 0
    | 1 -> 1
    | n -> fib (n - 1) + fib (n - 2)
 
let main() =
    Console.WriteLine("fib 5: {0}", (fib 5))
 
main()