Teachers and students of a primary school participated in the "Red Journey" revolutionary traditional education activity. After all boarded the bus, counting the number of people found that each bus could hold 35 people, the first 17 buses were full of teachers and students, and the 18th bus was full with only 4 people. How many people participated in this "Red Journey" activity?
某小学师生参加"红色之旅"革命传统教育活动．全部上车后，清点人数发现：每辆车可乘坐35人，前17辆客车已坐满师生，第18辆车上差4人就坐满了．一共有多少人参加这次"红色之旅"活动？
<gadget id="calculator">35 * 18</gadget>
<output>630</output>

<gadget id="calculator">630 - 4</gadget>
<output>626</output>

<result>626</result>