TRS: { from(X) -> cons(X, n__from(s(X))), first(0(), Z) -> nil(), first(s(X), cons(Y, Z)) -> cons(Y, n__first(X, activate(Z))), sel(0(), cons(X, Z)) -> X, sel(s(X), cons(Y, Z)) -> sel(X, activate(Z)), from(X) -> n__from(X), first(X1, X2) -> n__first(X1, X2), activate(n__from(X)) -> from(X), activate(n__first(X1, X2)) -> first(X1, X2), activate(X) -> X} Fail