new (E → G ∧ F) → ((B → D) → (E ∧ F → (D → (A → ((A → E ∧ F) → (((G → B) → H) → (G ∧ (D → A) → (C ∧ H → H))))))))
intro
intro
intro
cases 2
intro
intro
intro
intro
cases 2
intro
cases 11
cases 2
cases 11
intro
cases 18
cases 2
cases 11
cases 18
exact 20