Third grade students participate in extracurricular interest groups. There are 20 people in the calligraphy group, 17 people in the music group, and 5 people in both groups. How many people in the third grade participated in these two interest groups?
三年级同学参加课外兴趣小组．参加书法组的有20人，参加音乐组的有17人，两个组都参加的有5人．三年级参加这两个兴趣小组的一共有多少人．
<gadget id="calculator">17 - 5</gadget>
<output>12</output>

<gadget id="calculator">20 + 12</gadget>
<output>32</output>

<result>32</result>