proposition: Lemma count_Forall : forall P l, Forall P l -> count P l = length l.
proof: Proof. Proof using. introv. rewrite~ Forall_eq_count_eq_length. Qed.
imports: TLC(LibTactics LibLogic LibOperation LibReflect LibProd LibNat LibInt LibOption LibWf) TLC(LibInt)