(VAR X Y Z)
(STRATEGY CONTEXTSENSITIVE 
  (0)
  (s)
  (nil)
  (cons 1)
  (fst 1 2)
  (from 1)
  (add 1 2)
  (len 1)
)
(RULES 
fst(0,Z) -> nil
fst(s(X),cons(Y,Z)) -> cons(Y,fst(X,Z))
from(X) -> cons(X,from(s(X)))
add(0,X) -> X
add(s(X),Y) -> s(add(X,Y))
len(nil) -> 0
len(cons(X,Z)) -> s(len(Z))
)