Among extracurricular club activities, there are 15 people participating in the music club, 13 people participating in the art club, and 3 people participating in both. How many people join the music club and the art club?
课外社团活动中，参加音乐社团的有15人，参加美术社团的有13人，两样都参加的有3人，参加音乐、美术社团的一共有多少人．
<gadget id="calculator">13 - 3</gadget>
<output>10</output>

<gadget id="calculator">15 + 10</gadget>
<output>25</output>

<result>25</result>