(STRATEGY
    INNERMOST)

(VAR
    X)
(DATATYPES
    A = µX.< mark(X), c, d, ok(X) >)
(SIGNATURES
    active :: [A] -> A
    proper :: [A] -> A
    g :: [A] -> A
    h :: [A] -> A
    top :: [A] -> A)
(RULES
    active(g(X)) -> mark(h(X))
    active(c()) -> mark(d())
    active(h(d())) -> mark(g(c()))
    proper(g(X)) -> g(proper(X))
    proper(h(X)) -> h(proper(X))
    proper(c()) -> ok(c())
    proper(d()) -> ok(d())
    g(ok(X)) -> ok(g(X))
    h(ok(X)) -> ok(h(X))
    top(mark(X)) -> top(proper(X))
    top(ok(X)) -> top(active(X)))