YES
O(n^2)
TRS:
 {   f(f(X)) -> f(a(b(f(X)))),
  f(a(g(X))) -> b(X),
        b(X) -> a(X)}
 Natural interpretation:
  Strict:
   {   f(f(X)) -> f(a(b(f(X)))),
    f(a(g(X))) -> b(X),
          b(X) -> a(X)}
  Weak:
   {}
  Interpretation class: deltarestricted
  [g](delta, X0) = + 0*X0 + 2 + 1*X0*delta + 0*delta
  [b](delta, X0) = + 0*X0 + 0 + 1*X0*delta + 1*delta
  [a](delta, X0) = + 0*X0 + 0 + 1*X0*delta + 0*delta
  [f](delta, X0) = + 0*X0 + 2 + 2*X0*delta + 0*delta
  g_tau_1(delta) = delta/(0 + 1 * delta)
  b_tau_1(delta) = delta/(0 + 1 * delta)
  a_tau_1(delta) = delta/(0 + 1 * delta)
  f_tau_1(delta) = delta/(0 + 2 * delta)
  
  Qed