(STRATEGY
    INNERMOST)

(VAR
    x y)
(DATATYPES
    A = µX.< 0, s(X) >)
(SIGNATURES
    + :: [A x A] -> A
    * :: [A x A] -> A
    twice :: [A] -> A
    - :: [A x A] -> A
    f :: [A] -> A)
(RULES
    +(0(),y) -> y
    +(s(x),y) -> s(+(x,y))
    *(x,0()) -> 0()
    *(x,s(y)) -> +(x,*(x,y))
    twice(0()) -> 0()
    twice(s(x)) -> s(s(twice(x)))
    -(x,0()) -> x
    -(s(x),s(y)) -> -(x,y)
    f(s(x)) -> f(-(*(s(s(x))
                    ,s(s(x)))
                  ,+(*(s(x),s(s(x))),s(s(0()))))))