There are 45 people in class 3 and 1 participating in music interest groups, each of whom participates in at least one kind, 22 people singing and 28 people dancing, how many people participate in the two interest groups at least.
三1班有45人参加音乐兴趣小组，每人至少参加一种，唱歌的有22人，舞蹈的有28人，参加两种兴趣小组的至少有多少人．
<gadget id="calculator">28 - 45</gadget>
<output>-17</output>

<gadget id="calculator">22 + (-17)</gadget>
<output>5</output>

<result>5</result>