YES
O(n^2)
TRS:
 {f(a(), b()) -> f(a(), c()),
  f(c(), d()) -> f(b(), d())}
 Natural interpretation:
  Strict:
   {f(a(), b()) -> f(a(), c()),
    f(c(), d()) -> f(b(), d())}
  Weak:
   {}
  Interpretation class: deltarestricted
  [d](delta) = + 0 + 0*delta
  [b](delta) = + 0 + 3*delta
  [c](delta) = + 2 + 0*delta
  [a](delta) = + 0 + 0*delta
  [f](delta, X1, X0) = + 0*X0 + 0*X1 + 0 + 1*X0*delta + 2*X1*delta + 0*delta
  
  
  
  
  f_tau_1(delta) = delta/(0 + 2 * delta)f_tau_2(delta) = delta/(0 + 1 * delta)
  
  Qed