(STRATEGY
    INNERMOST)

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