The teacher wants to notify 7 students to hold a meeting, and call to notify one of them every minute, at least how many minutes.
老师要通知7名同学开会，打电话一分钟通知一个，最少只要多少分分钟．
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<result>3</result>