Ocaml: fix the code to realize

hanoi: int -> int: hanoin returns the optimal number of moves in the Tower of Hanoi puzzle for a tower of height n. This must be a recursive implementation, using the equation h, = 2. ha-1 +1. let hanoi_tests = [ (1, 1); (2, 2) ] let hanoi (n: int) : int = if n int: hanoin returns the optimal number of moves in the Tower of Hanoi puzzle for a tower of height n. This must be a recursive implementation, using the equation h, = 2. ha-1 +1. let hanoi_tests = [ (1, 1); (2, 2) ] let hanoi (n: int) : int = if n