(STRATEGY
    INNERMOST)

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