3.0 1 f y f g x b g f f g f a b y x 1 2 1 2 a 0 0 1 0 1 b 0 1 0 5 4 g 1 0 0 1 2 1 0 1 0 1 f 2 0 1 1 1 1 2 0 0 1 2 1 Example 23