new G ∧ F → (A → ((C → E ∧ F) → (((C → F) → B) → ((E → D) → (E ∧ D → (G ∨ C → (((G ∨ B → A) → ((E ∨ C) ∧ (A → F) → A ∨ (D → A))) → ((E → D) ∨ (B → D)) ∨ D)))))))
intro
cases 0
intro
intro
intro
intro
intro
cases 7
cases 0
cases 7
intro
cases 0
cases 7
intro
cases 0
cases 7
left
left
exact 6