I solved the challenge by constructing an alternation that exactly matches each of the given target items and nothing else. I listed the literals exactly as they appear and escaped only the dots in the email addresses so they are treated as literal periods. I then wrapped the entire alternation in start (^) and end ($) anchors to ensure that the match is exactly one of the provided items, and not a substring of any other text. This pattern thus will match exactly the 11 given targets and nothing else.