(STRATEGY
    INNERMOST)

(VAR
    x)
(DATATYPES
    A = µX.< 0, s(X), +(X, X) >)
(SIGNATURES
    sum :: [A] -> A
    sum1 :: [A] -> A)
(RULES
    sum(0()) -> 0()
    sum(s(x)) -> +(sum(x),s(x))
    sum1(0()) -> 0()
    sum1(s(x)) -> s(+(sum1(x)
                     ,+(x,x))))