Qianjin Cinema has 1,400 seats. Yucai Primary School has 31 classes with an average of 45 students in each class. These students have all gone to the movies. How many vacant seats are there in the theater?
千金电影院有1400个座位，育才小学有31个班，平均每班45人，这些同学都去看电影了，电影院还有多少个空座位？
<gadget id="calculator">31 * 45</gadget>
<output>1_395</output>

<gadget id="calculator">1_400 - 1_395</gadget>
<output>5</output>

<result>5</result>