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