18 table tennis players participate in a singles match, paired in pairs for a knockout match, how many games will be played in total to determine the champion.
18名乒乓球运动员参加单打比赛，两两配对进行淘汰赛，要决出冠军，一共要比赛多少场．
<gadget id="calculator">18 - 1</gadget>
<output>17</output>

<result>17</result>