YES
O(n)
TRS:
 {f(f(a(), x), a()) -> f(f(a(), f(a(), a())), x)}
 DUP: We consider a non-duplicating system.
  Trs:
   {f(f(a(), x), a()) -> f(f(a(), f(a(), a())), x)}
  BOUND:
   Automaton:
    {
         a_1() -> 3,
         a_0() -> 2,
     f_1(5, 4) -> 2,
     f_1(5, 2) -> 2,
     f_1(3, 4) -> 5,
     f_1(3, 3) -> 4,
     f_0(2, 2) -> 2
    }
   Strict:
    {}
   Qed