(STRATEGY
    INNERMOST)

(VAR
    b x y)
(DATATYPES
    A = µX.< 0, s(X) >)
(SIGNATURES
    minus :: [A x A] -> A
    div :: [A x A] -> A
    f :: [A x A x A] -> A)
(RULES
    minus(x,x) -> 0()
    minus(s(x),s(y)) -> minus(x,y)
    minus(0(),x) -> 0()
    minus(x,0()) -> x
    div(s(x),s(y)) -> s(div(minus(x
                                 ,y)
                           ,s(y)))
    div(0(),s(y)) -> 0()
    f(x,0(),b) -> x
    f(x,s(y),b) -> div(f(x
                        ,minus(s(y),s(0()))
                        ,b)
                      ,b))