1. Consider the following grammar S -> A A -> aaB | bAA B -> b | aB Suppose that a string generated by this grammar contains n occurrences of "a" and m occurrences of "b". 1. What is the shortest string that this grammar generates? 2. Can n be greater than m? If so, give an example that illustrates this. 3. Can n be less than m? If so, give an example that illustrates this. 4. Can n be equal to m? If so, give an example that illustrates this. 5. Can this grammar be parsed by a top-down parser using one lookahead only? Explain briefly.