Consider the set of all strings over the alphabet { a, b, /, . }{ a, b, /, . } that represent an ri (resource identifier). an ri is a non-empty sequence of forward-slash (//) separated non-empty strings composed of only the symbols aa and bb. the first string in the sequence may optionally be the .. symbol instead of a string composed of aa and bb. each string is separated by only one slash, and there are no slashes at the beginning or end of the sequence. write a regular expression, conformant with the syntax restrictions given at the top of this question, describing the set of strings as given above. write a (right) regular grammar describing the same set of strings.