YES
O(n^2)
TRS:
 {b(b(a(x))) -> a(b(b(x))),
     a(a(x)) -> b(b(x))}
 Natural interpretation:
  Strict:
   {b(b(a(x))) -> a(b(b(x))),
       a(a(x)) -> b(b(x))}
  Weak:
   {}
  Interpretation class: deltarestricted
  [a](delta, X0) = + 1*X0 + 1 + 1*X0*delta + 0*delta
  [b](delta, X0) = + 1*X0 + 0 + 1*X0*delta + 0*delta
  a_tau_1(delta) = delta/(1 + 1 * delta)
  b_tau_1(delta) = delta/(1 + 1 * delta)
  
  Qed