There are 28 people in class 3 and 2, 13 people bought comic books, 14 people bought story books, and 6 people bought both kinds of books. How many people bought comic books and story books?
三2班有28人，其中买漫画书的有13人，买故事书的有14人，两种书都买的有6人，买漫画书和故事书的一共有多少人？
<gadget id="calculator">14 - 6</gadget>
<output>8</output>

<gadget id="calculator">13 + 8</gadget>
<output>21</output>

<result>21</result>