(VAR X Y Z X1 X2)
(RULES 
2nd(cons(X,n__cons(Y,Z))) -> activate(Y)
from(X) -> cons(X,n__from(n__s(X)))
cons(X1,X2) -> n__cons(X1,X2)
from(X) -> n__from(X)
s(X) -> n__s(X)
activate(n__cons(X1,X2)) -> cons(activate(X1),X2)
activate(n__from(X)) -> from(activate(X))
activate(n__s(X)) -> s(activate(X))
activate(X) -> X
)