(STRATEGY
    INNERMOST)

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