Ao Zema, Xiao Mei, and Ou Ou play Go, two people in each game, and the loser withdraws and replaces another player, and this continues. When Ao Zema has played 9 games and Xiao Mei has played 6 games, Ou Ou has played Go at most. How many games did you play?
奥斑马、小美、欧欧三人下围棋，每场两人，输者退下换另一人，这样继续下去，当奥斑马下了9场，小美下了6场时，欧欧最多下了多少场．
<gadget id="calculator">7 + 4</gadget>
<output>11</output>

<result>11</result>