On Wednesday, a war was raging in the Hyatt Regency Hotel in Baltimore, Md.

Well, sort of.

A team of seasoned computer scientists (led by a guy with a vast experience working for “a three letter agency”) was hacking into the computers of teams made of high school students. For three and a half hours five teenagers had to cleanse and protect eight computers plagued by weak passwords, firewall with open ports and routers with default settings on.

It was all in good spirits, though.

The cyber battle was a part of the tenth annual National Youth Cyber Defense Competition, or CyberPatriot, a program created by the Air Force Association where middle school and high school students face off in cyberskills. More than as 5584 teams from around the world (1180 more than last year) squared off in three divisions: high school, middle school and U.S. Junior Reserve Officers (JROTC).

Jay Gehringer, 60, a computer science professor at North Hollywood High School (NHHS) in Los Angeles and the coach of the first and the second placed teams in the Open Division, said the students had to work as a team and act very quickly amid high pressure.

“Imagine if you had a house where all the doors and windows are wide open and you have to go around start locking everything and in some cases installing the locks, all while trying to kick out the burglars” he told FORBES.

“It was really stressful” attests senior Jeron Mendelsohn, 18, who was a part of the NHHS team named Togo (after the heroic 1920s Alaska sled dog) that won the Open Division competition for second year in a row. His teammate, senior Kyle Gusdorf, 18, added that throughout the year they practiced for three hours a week and that number jumped to eight hours as the date was approaching.

“The program is growing very fast, we have about 30% more teams every year” says the program director for the main sponsor of the event, Northrop Grumman’s Diane Miller. “Students are telling and bringing their friends.”

This year it included teams from countries like South Korea, UAE and Hungary. It was also the first year where an all girls team reached the finals, where 12 teams faced off in each division.

“Competition has to get more and more challenging every year because the students are getting so good at recognizing vulnerabilities” says Bernie Skoch, a commissioner of the competition and a retired brigadier air force general, who became involved with CyberPatriot after an unsuccessful run for Congress in Arkansas.

At a time when cybersecurity makes headlines for its vulnerability, ranging from corporate attacks like the Sony or Equifax breaches, to government and political calamity such as the alleged Russian meddling in the U.S. elections, the cybersecurity experts deficiency is omnipresent. A recent report from CyberSecurity Ventures predicts that by 2021 there will be 3.5 million unfulfilled jobs in the field.

“There are a lot of career paths for the students to choose from, but there is not one that is psychological and financially more rewarding than cybersecurity” Skoch says.

Speaking of rewarding, the winners of the competition got $2,000 each, and the North Hollywood students each will receive a laptop from Los Angeles Unified School District. That is without counting the school popularity which is hard to measure.

It all comes at a price, though.

“The CyberPatriots are seen as computer wizards or the IT Helpdesk” adds Mendelsohn who is going to study computer science at Berkeley next year. “Which means that now I’ll have to fix all of my friends’ computers.”