app app plus 0 y y app app plus app s x y app s app app plus x y app app sumwith f nil nil app app sumwith f app app cons x xs app app plus app f x app app sumwith f xs app 2 plus 0 0 0 s 0 sumwith 0 nil 0 cons 0 FULL ./TRS/higher-order/AotoYam/004.trs