Local Open Scope logic.
(*Require Import tweetnacl20140427.split_array_lemmas.*)
unfold Byte.max_unsigned, Int.max_unsigned. simpl. omega. Qed.

Lemma app_Znth2: forall (A : Type) {d: Inhabitant A}(l l' : list A) (n : Z),
(Zlength l <= n) -> Znth n (l ++ l') = Znth (n - Zlength l) l'.