YES(?,O(n^1))

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

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {2}
   transitions:
    b1(9) -> 10*
    b1(8) -> 9*
    a1(7) -> 8*
    a0(1) -> 2*
    b0(1) -> 1*
    1 -> 7*
    10 -> 8,2
  problem:
   
  Qed