(STRATEGY
    INNERMOST)

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