Input TRS:
    1: f(n__f(n__a())) -> f(n__g(n__f(n__a())))
    2: f(X) -> n__f(X)
    3: a() -> n__a()
    4: g(X) -> n__g(X)
    5: activate(n__f(X)) -> f(X)
    6: activate(n__a()) -> a()
    7: activate(n__g(X)) -> g(activate(X))
    8: activate(X) -> X
Number of Rules: 8
Direct POLO(Sum) ... failed.