Define a context-free grammar in BNF for the following language:

Define a regular grammar which defines a language whose sentences are the set of all strings of letters which contain each of the five vowels exactly once and in order. Use only lower case letters. For example, your regular grammar must be capable of generating the strings aeiou, ateitou, and, zaeztiouzpg, but not aeou aaeiou and aeitgaou. You may use only the*, +, [], and^a metacharacters in your regular grammar