Military trainers perform a team performance and line up in a square queue. If the queue is extended horizontally and vertically, 15 more people need to be added. How many teachers and students are there in the queue performance?
军训师进行队伍表演，排成一个正方形队列，如果这个队列横，竖在增加一排，还需要补充15人，原来参加队列表演的师生有多少人？
<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">15 - 8</gadget>
<output>7</output>

<gadget id="calculator">7 * 7</gadget>
<output>49</output>

<result>49</result>