Input TRS:
    1: f(x,a(a(b(b(y))))) -> f(a(a(a(b(b(b(x)))))),y)
    2: f(a(x),y) -> f(x,a(y))
    3: f(b(x),y) -> f(x,b(y))
Number of Rules: 3
Direct QWPOS(max) ... failed.