This is just a basic problem to get everyone's feet wet in preparation of the rest of the CTF competition. It tests whether the player knows how to correctly enter a flag, which is necessary in order to get any points over the course of the competition, as well as informs the player what the format of the flags is.
To solve this challenge, just enter **MetaCTF{string_separated_with_und3rscores}** for an easy 50 points.