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