(VAR f x xs y ys )
(RULES 
        app(app(map,f),nil) -> nil
        app(app(map,f),app(app(cons,x),xs)) -> app(app(cons,app(f,x)),app(app(map,f),xs))
        app(app(le,0),y) -> true
        app(app(le,app(s,x)),0) -> false
        app(app(le,app(s,x)),app(s,y)) -> app(app(le,x),y)
        app(app(maxlist,x),app(app(cons,y),ys)) -> app(app(if,app(app(le,x),y)),app(app(maxlist,y),ys))
        app(app(maxlist,x),nil) -> x
        app(height,app(app(node,x),xs)) -> app(s,app(app(maxlist,0),app(app(map,height),xs)))
        
)