new (B → A ∧ A) → (D ∧ B → (A ∧ B → (C → ((B ∧ D) ∧ D ∨ (B ∨ (D → A))) ∧ C ∨ ((A ∧ D ∨ D) ∨ ((B → A) ∨ (A → B ∨ D)) → B ∧ B))))
intro
intro
cases 1
intro
cases 4
intro
cases 1
cases 4
left
constructor
left
constructor
constructor
exact 3
exact 2
exact 2
exact 7