Goal:
    A : Type  n : nat  hd : A  tl : list A  H : S n < #|hd :: tl|
  ============================
   (S n ≤ #|tl|)


DEBUG:Going to execute:
match goal with
           | H:_ ∧ _ |- _ => destruct H
           | H:(_ * _)%type |- _ => destruct H
           end