YES
Time: 0.002051
TRS:
 {f(f(a(), x), a()) -> f(f(a(), f(a(), a())), x)}
 DP:
  DP:
   {f#(f(a(), x), a()) -> f#(f(a(), f(a(), a())), x),
    f#(f(a(), x), a()) -> f#(a(), f(a(), a())),
    f#(f(a(), x), a()) -> f#(a(), a())}
  TRS:
  {f(f(a(), x), a()) -> f(f(a(), f(a(), a())), x)}
  UR:
   {}
   EDG:
    {}
    STATUS:
     arrows: 1.000000
     SCCS (0):