new F ∧ (F → B) → ((D ∨ A → A) → ((B ∧ F) ∧ (D ∧ A) → (((E → C) → A) ∧ C → (B → C))) ∧ B)
intro
cases 0
intro
cases 0
constructor
intro
cases 6
cases 0
cases 6
cases 7
cases 8
cases 11
cases 12
intro
cases 21
cases 0
cases 6
cases 7
cases 8
cases 11
cases 12
cases 21
cases 26
cases 27
intro
cases 0
cases 6
cases 7
cases 8
cases 11
cases 12
cases 21
cases 26
cases 27
cases 45
cases 46
exact 23
apply 2
exact 1