Input TRS:
    1: f(x,a(b(y))) -> f(a(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 POLO(Sum) ...Direct QLPOS ...Direct QKBOS ... failed.