The school organized the fourth grade students to visit the tombs of the martyrs. I rented 7 cars, each car can take up to 43 people, and finally found that there are still 20 vacant seats. How many fourth-grade students did the school organize to participate in the sweeping activities?
学校组织四年级的同学去祭扫烈士墓．租用了7辆车，每辆车最多可以乘坐43人，最后发现还有20个空座位．学校一共组织了多少名四年级的同学去参加祭扫活动？
<gadget id="calculator">43 * 7</gadget>
<output>301</output>

<gadget id="calculator">301 - 20</gadget>
<output>281</output>

<result>281</result>