A number of books have been added to the school library. There are 354 books on science and technology, and 123 books on literature are twice the number of books on science and technology. How many books are there on literature?
学校图书室添置了一批图书，科技类图书有354本，文学类图书的本数比科技类的2倍多123本，文学类图书有多少本？
<gadget id="calculator">354 * 2</gadget>
<output>708</output>

<gadget id="calculator">708 + 123</gadget>
<output>831</output>

<result>831</result>