The school library bought back 340 science and technology books and 230 literature and art books. The number of story books bought back is three times the sum of the number of science and technology books and literary books. How many story books are bought back?
学校图书室买回科技书340本，文艺书230本．买回的故事书是科技书和文艺书本数的和的3倍，买回的故事书有多少本？
<gadget id="calculator">340 + 230</gadget>
<output>570</output>

<gadget id="calculator">570 * 3</gadget>
<output>1_710</output>

<result>1_710</result>