There are 38 people in Class 3 and 2, 18 people participated in the chorus team, 15 people participated in the dance team, and 7 of them participated in both. So how many people did not participate in these two interest groups?
三2班共38人，参加合唱队的有18人，参加舞蹈队的有15人，其中7人两项都参加．那么有多少人没有参加这两项兴趣小组．
<gadget id="calculator">15 - 7</gadget>
<output>8</output>

<gadget id="calculator">18 + 8</gadget>
<output>26</output>

<gadget id="calculator">38 - 26</gadget>
<output>12</output>

<result>12</result>