The United States is number one in math after 21 years. A six-person team of young adult Americans Team USA led by Carnegie Mellon professor Po-Shen Loh bested teams from China, South Korea, and more to win the 2015 International Mathematical Olympiad (IMO) held in Thailand this month which was hailed as the “hardest ever” competition by The Guardian.

The White House even tweeted, “Go Team USA! America took first place in the International Mathematical Olympiad for the first time since 1994,” with an attached photo of a letter of congratulations from President Barack Obama.

Indian Americans Shyam Narayanan, 17, and Yang Liu, 18, were part of the six-member team that rose to the top at the IMO, a feat that hasn’t been accomplished by the U.S. team since 1994.

Narayanan’s parents are of Indian origin while Liu’s father is Indian  and his mother is chin ease.

Members of the U.S. team included Ryan Alweiss, Allen Liu, Yang Liu, Narayanan, and David Stoner, all of whom were awarded gold medals; and Michael Kural, who earned a silver medal, just one point away from the gold.

According to the Mathematical Association of America (MAA), the competition involves six problems taken in sets of three during 4.5 hour sessions (held across two days)—no calculators. Each team member attempts the problems, and team totals are based on the number of points each individual scores. The US earned 185 to take the gold while China earned runner-up honors with 181. It’s the US’s fifth victory overall. China has the most competition wins with 19 all-time, including winning four of the last five competitions heading into the 2015 edition.