Give a BNF grammar for each of the languages below:

1. The set of all strings consisting of a uppercase letter followed by zero or more additional characters, each of which is either a uppercase letter or one of the characters 0 through 9.

2. The set of all strings consisting of the keyword begin, followed by zero or more statements with a semicolon after each one, followed by the keyword end. Use the nonterminal for statements, and do not give productions for it.

3. The set of all strings consisting of one or more as, with a comma between each a and the next. (There should be no comma before the first or after the last a.)