new I ∧ A → ((C → H ∧ J) → (B ∧ D → (C → (D → (E ∨ I → ((F ∨ D → D) → (F ∧ (D ∨ K) → E) ∨ D))))))
intro
cases 0
intro
intro
cases 4
intro
intro
intro
intro
cases 0
cases 4
right
exact 6