new ((B → E) → D) → ((G → D) → (F ∧ B → ((C → G) → (E ∨ D → ((E ∧ G) ∧ (E ∧ A → D) → (G → E ∧ G))))))
intro
intro
intro
cases 2
intro
intro
cases 2
intro
cases 9
cases 2
cases 9
cases 10
cases 14
intro
cases 2
cases 9
cases 10
cases 14
cases 23
exact 10