data Foo a = F (Foo a -> a -> a)

foo :: Foo a -> Foo a -> a -> a
foo (F f) g x = f g x

--m = F (\f x -> if x > 10 then x else foo f m (x + 1))
m = F (\f x -> foo f m (x + 1))
n = F (\f x -> foo f n (x + 1))

main = print $ foo n m 5