There are 50 students in a class, 28 students participated in the Chinese competition, 23 students participated in the mathematics competition, and 10 students participated in the known language and mathematics competition. How many people did not participate in the language and mathematics competition?
某班有50名学生，参加语文竞赛的有28人，参加数学竞赛的有23人，已知语、数竞赛参加的有10人，那么语、数竞赛都没有参加的有多少人．
<gadget id="calculator">23 - 10</gadget>
<output>13</output>

<gadget id="calculator">28 + 13</gadget>
<output>41</output>

<gadget id="calculator">50 - 41</gadget>
<output>9</output>

<result>9</result>