∀ {α : Type u_1} [inst : DecidableEq α] {a : α} (a_1 : α) (l₁ l₂ : List α) (h_3 : a_1 = a)
  (h_5 : List.count a (a_1 :: l₁) ≤ List.count a l₂),
  (List.findIdxs (fun x => decide (x = a)) l₂)[(List.filter (fun x => decide (x = a)) l₁).length] < l₂.length