please solve it complete in 30 minute

(b) Argue that the language {a"b"|n=0, 1,...} U{b"a")n = 0, 1,...} over the alphabet {a,b} belongs to the complexity class P. You don't need to give a formal but merely an implementation level description of the relevant Turing machine, i.e., show with sufficient detail why such a machine exists, and that its complexity is polynomial. [5]