Input TRS:
    1: f(n__a(),X,X) -> f(activate(X),b(),n__b())
    2: b() -> a()
    3: a() -> n__a()
    4: b() -> n__b()
    5: activate(n__a()) -> a()
    6: activate(n__b()) -> b()
    7: activate(X) -> X
Number of Rules: 7
Direct QWPOS(Sum) ... failed.