There are 4 story books, 3 comic books, and 2 literature and art books in the book box. How many books should be taken out at a time to ensure that there is at least one book of each kind.
书箱里有4本故事书，3本连环画，2本文艺书，一次至少取出多少本书才能保证每种书至少有一本．
<gadget id="calculator">4 + 3 + 1</gadget>
<output>8</output>

<result>8</result>