There are 45 people in Class 4, 24 of them participated in the Chinese competition, 28 participated in the mathematics competition, and 11 participated in both competitions. How many people in class 4 did not participate in the two competitions?
四1班有45人，其中24人参加了语文竞赛，28人参加了数学竞赛，11人两项比赛都参加了．四1班有多少人两项比赛都没参加．
<gadget id="calculator">28 - 11</gadget>
<output>17</output>

<gadget id="calculator">24 + 17</gadget>
<output>41</output>

<gadget id="calculator">45 - 41</gadget>
<output>4</output>

<result>4</result>