(STRATEGY
    INNERMOST)

(VAR
    M N X X1 X2)
(DATATYPES
    A = µX.< tt, 0, s(X), and(X, X), plus(X, X), x(X, X) >)
(SIGNATURES
    a__and :: [A x A] -> A
    a__plus :: [A x A] -> A
    a__x :: [A x A] -> A
    mark :: [A] -> A)
(RULES
    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))