TRS:
 {   a__and(tt(), X) -> mark(X),
     a__plus(N, 0()) -> mark(N),
    a__plus(N, s(M)) -> s(a__plus(mark(N), mark(M))),
        a__x(N, 0()) -> 0(),
       a__x(N, s(M)) -> a__plus(a__x(mark(N), mark(M)), mark(N)),
   mark(and(X1, X2)) -> a__and(mark(X1), X2),
  mark(plus(X1, X2)) -> a__plus(mark(X1), mark(X2)),
     mark(x(X1, X2)) -> a__x(mark(X1), mark(X2)),
          mark(tt()) -> tt(),
           mark(0()) -> 0(),
          mark(s(X)) -> s(mark(X)),
      a__and(X1, X2) -> and(X1, X2),
     a__plus(X1, X2) -> plus(X1, X2),
        a__x(X1, X2) -> x(X1, X2)}
 Fail