Alphabet: "ab"
the States:  1 2 3 4 5 6 7
Start state: 1
Accepting states: 2 3 5 6 7
Dead state: 4

(1, a) -> 2
(1, b) -> 6
(2, a) -> 3
(2, b) -> 5
(3, a) -> 4
(3, b) -> 3
(4, a) -> 4
(4, b) -> 4
(5, a) -> 4
(5, b) -> 4
(6, a) -> 5
(6, b) -> 7
(7, a) -> 7
(7, b) -> 4