#import nat
#import list
#import pair
#
#def fib_iter n a b =
#    match n
#        with zero => add a b
#        with succ n' => fib_iter n' b (add a b)
#
#def fib n =
#    match n
#        with zero => zero
#        with succ n' => (
#            match n'
#                with zero => succ zero
#                with succ n'' => fib_iter n'' zero (succ zero)
#            )
#
#def main : Nat = map (fun n => println (show (fib n))) (up_to (add three ten))
def main : Top = top