YES
O(n^2)
TRS:
 { f(x, a()) -> x,
  f(x, g(y)) -> f(g(x), y)}
 Natural interpretation:
  Strict:
   { f(x, a()) -> x,
    f(x, g(y)) -> f(g(x), y)}
  Weak:
   {}
  Interpretation class: deltarestricted
  [g](delta, X0) = + 1*X0 + 1 + 0*X0*delta + 0*delta
  [a](delta) = + 0 + 1*delta
  [f](delta, X1, X0) = + 1*X0 + 1*X1 + 0 + 1*X0*delta + 0*X1*delta + 0*delta
  g_tau_1(delta) = delta/(1 + 0 * delta)
  
  f_tau_1(delta) = delta/(1 + 0 * delta)f_tau_2(delta) = delta/(1 + 1 * delta)
  
  Qed