app app app fold f x nil x app app app fold f x app app cons y z app app f y app app app fold f x z app app plus 0 y y app app plus app s x y app s app app plus x y app app times 0 y 0 app app times app s x y app app plus app app times x y y sum app app fold add 0 prod app app fold mul app s 0 2.2 app app app fold f x app app cons y z app f y app app times app s x y app app times x y app app plus app s x y app s app app plus x y sum app fold add prod app fold mul prod app s 0 app app plus app s x y app app plus x y app app times app s x y app times x prod app app fold mul app s 0 app app times app s x y app plus app app times x y app app app fold f x app app cons y z app app app fold f x z app app app fold f x app app cons y z app app f y app app app fold f x z sum app app fold add 0 app app plus app s x y app plus x app app times app s x y app app plus app app times x y y true prod app s 0 false sum app app fold add 0 false prod app fold mul false sum app fold add false prod app app fold mul app s 0 false app app app fold f x app app cons y z app app f y app app app fold f x z app app app fold f x app app cons y z app app app fold f x z app app app fold f x app app cons y z app f y true Failed! NaTT certifiable-1.6