Three martial arts teams will compete in a group arena. Each team will send 6 players. First, one player from each of the two teams will stop the ring competition. Step off the stage, and a player from a different team from the winner will come on stage...Continue. When all players from two teams are defeated, the remaining team wins. At this time, how many contests should be carried out at least.
三个武术队进行擂台赛，每队派6名选手，先由两队各出1名选手止擂台比武，负者下台，不再上台，胜者继续同其它队的一位选手比武，负者下台，和胜者不同队的双一位选手上台…继续下去．当有两个队的选手全部被击败时，余下的队即获胜．这时最少要进行多少场比武．
<gadget id="calculator">6 + 6</gadget>
<output>12</output>

<result>12</result>