(VAR X Y)
(STRATEGY CONTEXTSENSITIVE 
  (fact 1)
  (if 1)
  (zero 1)
  (s 1)
  (0)
  (prod 1 2)
  (p 1)
  (add 1 2)
  (true)
  (false)
)
(RULES 
fact(X) -> if(zero(X),s(0),prod(X,fact(p(X))))
add(0,X) -> X
add(s(X),Y) -> s(add(X,Y))
prod(0,X) -> 0
prod(s(X),Y) -> add(Y,prod(X,Y))
if(true,X,Y) -> X
if(false,X,Y) -> Y
zero(0) -> true
zero(s(X)) -> false
p(s(X)) -> X
)