Help me get the result, please.

[nutflush]

The supplied regular expression defines a pattern that the plaintext string matches. Many strings will match this regular expression, but only one of them, when run through an md5 hasher will produce the correct output.

Here is a great resource for determining what that regular expression really means: http://www.regular-expressions.info/quickstart.html

Hint: there are 6,652,800 possible plaintext strings that can be generated by this regular expression

If you aren't willing to do the research / work to solve the problem, perhaps you aren't fit to win the game.