(STRATEGY
    INNERMOST)

(VAR
    X X1 X2)
(DATATYPES
    A = µX.< 0, cons(X, X), f(X), s(X), p(X) >)
(SIGNATURES
    a__f :: [A] -> A
    a__p :: [A] -> A
    mark :: [A] -> A)
(RULES
    a__f(0()) -> cons(0(),f(s(0())))
    a__f(s(0())) ->
      a__f(a__p(s(0())))
    a__p(s(X)) -> mark(X)
    mark(f(X)) -> a__f(mark(X))
    mark(p(X)) -> a__p(mark(X))
    mark(0()) -> 0()
    mark(cons(X1,X2)) ->
      cons(mark(X1),X2)
    mark(s(X)) -> s(mark(X))
    a__f(X) -> f(X)
    a__p(X) -> p(X))