new E ∧ B → ((E ∨ D → C) → (B ∧ E → (A ∨ B → (C ∧ A → (B → (B → B ∨ E))))))
intro
cases 0
intro
intro
cases 4
intro
intro
cases 8
cases 0
cases 4
cases 8
intro
cases 0
cases 4
cases 8
intro
cases 0
cases 4
cases 8
left
exact 2