YES
O(n^2)
TRS:
 {f(a()) -> g(a()),
     b() -> a(),
  g(b()) -> f(b())}
 Natural interpretation:
  Strict:
   {f(a()) -> g(a()),
       b() -> a(),
    g(b()) -> f(b())}
  Weak:
   {}
  Interpretation class: deltarestricted
  [a](delta) = + 0 + 0*delta
  [g](delta, X0) = + 1*X0 + 0 + 3*X0*delta + 2*delta
  [b](delta) = + 3 + 2*delta
  [f](delta, X0) = + 1*X0 + 0 + 0*X0*delta + 3*delta
  
  g_tau_1(delta) = delta/(1 + 3 * delta)
  
  f_tau_1(delta) = delta/(1 + 0 * delta)
  
  Qed