Input TRS:
    1: active(g(X)) -> mark(h(X))
    2: active(c()) -> mark(d())
    3: active(h(d())) -> mark(g(c()))
    4: proper(g(X)) -> g(proper(X))
    5: proper(h(X)) -> h(proper(X))
    6: proper(c()) -> ok(c())
    7: proper(d()) -> ok(d())
    8: g(ok(X)) -> ok(g(X))
    9: h(ok(X)) -> ok(h(X))
    10: top(mark(X)) -> top(proper(X))
    11: top(ok(X)) -> top(active(X))
Number of Rules: 11
Direct QWPOS(Sum) ... failed.