init :: (Sized a) => Node a -> Node a
init (Node s n) = Node (s - size (V.last n)) (V.force (V.init n))
init :: (Sized a) => Node a -> Node a
init (Node s n) = Node (s - size (V.last n)) (V.force (V.init n))
init (Node s n) = Node (s - size (V.last n)) (V.force (V.init n))