There is a bookshelf in Class 6 and 1, and 40 students can borrow it at will. How many books should there be on the bookshelf to ensure that at least one student can borrow two or more books?
六1班有个书架，40名同学可以任意借阅，试问书架上至少要多少本书，才能保证至少有一名同学能借到两本或两本以上的书？
<gadget id="calculator">40 + 1</gadget>
<output>41</output>

<result>41</result>