(VAR X Y Z )
(STRATEGY CONTEXTSENSITIVE
        (f 1) 
        (cons 1) 
        (g 1) 
        (0 ) 
        (s 1) 
        (sel 1 2) 
)
(RULES 
        f(X) -> cons(X, f(g(X)))
        g(0) -> s(0)
        g(s(X)) -> s(s(g(X)))
        sel(0, cons(X, Y)) -> X
        sel(s(X), cons(Y, Z)) -> sel(X, Z)
        
)