The school held a basketball and football competition. There were 11 people participating in the basketball game on May 2, and 15 people participating in the football game. Among them, 8 people participated in both. How many people participated in the May 2 game?
学校举办篮球足球大赛，五2参加篮球赛的有11人，参加足球赛的有15人，其中有8人两项都参加了，五2共有多少人参赛．
<gadget id="calculator">15 - 8</gadget>
<output>7</output>

<gadget id="calculator">11 + 7</gadget>
<output>18</output>

<result>18</result>