TRS:
 {           a__zeros() -> cons(0(), zeros()),
        a__and(tt(), X) -> mark(X),
       a__length(nil()) -> 0(),
  a__length(cons(N, L)) -> s(a__length(mark(L))),
          mark(zeros()) -> a__zeros(),
      mark(and(X1, X2)) -> a__and(mark(X1), X2),
        mark(length(X)) -> a__length(mark(X)),
     mark(cons(X1, X2)) -> cons(mark(X1), X2),
              mark(0()) -> 0(),
             mark(tt()) -> tt(),
            mark(nil()) -> nil(),
             mark(s(X)) -> s(mark(X)),
             a__zeros() -> zeros(),
         a__and(X1, X2) -> and(X1, X2),
           a__length(X) -> length(X)}
 Fail