Uncle Liu bought a pen with a unit price of 15.6 yuan and a book with a unit price of 15.4 yuan in a stationery store. He paid 50 yuan, how much should he get back?
刘大叔在文具店里买了一支单价15.6元的钢笔和一本15.4元的书，他付了50元，应找回多少元？
<result>1_819</result>