Goal:
  
  m : Z
  a : Z
  l : list Z
  IHl : forall n : Z, fold_left Z.max l n = m -> n = m \/ In m l
  n : Z
  H : Z.max n a = m
  ============================
   (n = m \/ a = m)


DEBUG:Going to execute:
intros; Zify.zify_pre_hook; zify_elim_let; zify_op