new B ∧ E → (B ∧ A → (A → (C → ((B → A) → ((C ∧ F) ∧ (F ∨ F) → (D → E) ∧ C ∨ (C ∧ F → C))))))
intro
cases 0
intro
cases 3
intro
intro
intro
cases 0
cases 3
intro
cases 13
cases 0
cases 3
cases 13
cases 14
cases 20
left
constructor
intro
cases 0
cases 3
cases 13
cases 14
cases 20
cases 31
exact 2
exact 7