new D ∧ E → (H ∧ F → (G → (((J → E) → C) → (((J → I) → G) → (J ∨ B → (B ∨ H → ((C → A) → D ∨ I)))))))
intro
cases 0
intro
cases 3
intro
intro
intro
intro
intro
cases 0
cases 3
intro
cases 0
cases 3
left
exact 1