A group of students went to a factory for an internship, and each factory was required to arrange the same number of students. The original plan was to arrange 28 students for each factory, so that one student could not be arranged; if one factory was reduced, all students could be assigned to the remaining students Go to the factory and ask: How many students are there in this batch?
有一批学生去工厂实习，要求每个工厂安排同样人数的学生，原计划每个工厂安排28人，这样有1个学生无法安排；如果减少一个工厂，则所有学生刚好能平均安排到剩下的工厂中去，问：这批学生有多少人？
<gadget id="calculator">28 + 1</gadget>
<output>29</output>

<gadget id="calculator">29 + 1</gadget>
<output>30</output>

<gadget id="calculator">28 * 30</gadget>
<output>840</output>

<gadget id="calculator">840 + 1</gadget>
<output>841</output>

<result>841</result>