Honghong went to Beijing to participate in a competition. In order to welcome her, the students who participated in the competition shook hands with her once. Honghong remembered shaking her hand 10 times. How many students participated in the competition?
红红去北京参加竞赛，参加竞赛的同学为了欢迎她，每人都和她握了一次手，红红记得握了10次，请问有多少同学参加竞赛？
<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<result>11</result>