new C → (J → ((G → B) → ((B → F ∧ I) → (A ∧ G → (E ∧ D → ((H ∨ J → C) → (F ∨ H → (I → A))))))))
intro
intro
intro
intro
intro
cases 4
intro
cases 7
intro
cases 4
cases 7
intro
cases 4
cases 7
intro
cases 4
cases 7
exact 5