The school library bought back 260 science and technology books and 380 literature and art books. The number of story books bought back is three times the number of science books and literary books combined. How many story books are bought back?
学校图书室买回科技书260本，文艺书380本．买回的故事书是科技书和文艺书本数和的3倍，买回的故事书有多少本？
<gadget id="calculator">260 + 380</gadget>
<output>640</output>

<gadget id="calculator">640 * 3</gadget>
<output>1_920</output>

<result>1_920</result>