2. (15 points). Consider the language \(L\) of strings over the alphabet \(\Sigma = \{a, b\}\) which contain an equal number of a's and b's, and the set of b's is consecutive in the string, e.g., ab, abba, aabb, abbbaa, aaabbbbbaa, etc. Note that \(\epsilon \in L\) for completeness (0 number of a's is equal to 0 number of b's, which are also consecutive). Show that this language is context-free by giving a context-free grammar.