import Mathlib

set_option maxHeartbeats 0

open BigOperators Real Nat Topology Rat

theorem mathd_algebra_185 (s : Finset ℤ) (f : ℤ → ℤ) (h₀ : ∀ x, f x = abs (x + 4))
  (h₁ : ∀ x, x ∈ s ↔ f x < 9) : s.card = 17 := by sorry