(a) Describe the formal language over the alphabet {1,2,3} generated by the context-free grammar whose non-terminals are and whose start symbol is and whose production rules are the following:

(1) ---> 122

(2) --->

(3) ---> 3

(4) ---> 3

(5) ---> 1

In other words, describe the structure of the strings generated by this grammar.

(b) Use the Pumping Lemma to prove that the language from part (a) is not regular.