(* Author: Eric Van Wyk
   Modified by: Michael Zhang *)

(* A function computing the Fibonacci sequence: 1, 1, 2, 3, 5, 8, ... *)

(* There is a bug in the following program.  Can you fix it? *)

let rec fib x =
  if x == 0 then 0 else
    (if x < 3 then 1 else fib (x-1) + fib (x-2))