YES(?,O(n^1))

Problem:
 b(a(b(x1))) -> b(a(a(a(b(x1)))))
 b(a(a(a(b(a(a(b(x1)))))))) -> b(a(a(b(a(a(b(a(a(a(b(b(x1))))))))))))
 b(a(a(a(b(a(a(a(b(x1))))))))) -> b(x1)
 b(a(a(a(b(b(b(x1))))))) -> b(b(b(a(a(a(b(x1)))))))
 b(a(a(b(b(x1))))) -> b(x1)
 b(b(a(a(b(x1))))) -> b(x1)
 b(a(a(a(b(a(b(x1))))))) -> b(x1)
 b(a(b(a(a(a(b(x1))))))) -> b(x1)

Proof:
 Bounds Processor:
  bound: 0
  enrichment: match
  automaton:
   final states: {2}
   transitions:
    b0(1) -> 2*
    a0(1) -> 1*
  problem:
   
  Qed