app app append nil ys ys app app append app app cons x xs ys app app cons x app app append xs ys app app flatwith f app leaf x app app cons app f x nil app app flatwith f app node xs app app flatwithsub f xs app app flatwithsub f nil nil app app flatwithsub f app app cons x xs app app append app app flatwith f x app app flatwithsub f xs app 2 append 0 nil 0 cons 0 flatwith 0 leaf 0 node 0 flatwithsub 0 FULL ./TRS/higher-order/AotoYam/013.trs