The best and most interesting part of this was about how they trained:

"The six student team is then brought together prior to the IMO for a three-and-one-half-week training program at Carnegie Mellon University, which is also organized by the MAA.... This year we also included ten international students — students on IMO teams from other countries. We paid for their airfare, hotel, food and teaching.... bringing in the international students gives the top US students peers. They always tell you — if you’re the smartest guy in the room, you’re in the wrong room. So we bring in these peers, who are actually at the same level as these top six. Of course that increases the level."