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