There are 16 students in a class, everyone participates in the competition, 8 students participate in the mathematics competition, and 11 students participate in the composition competition. At least how many people participate in both the mathematics competition and the composition competition.
某班共有16人，人人参加竞赛，参加数学竞赛的有8人，参加作文竞赛的有11人，至少有多少人既参加数学竞赛又参加作文竞赛．
<gadget id="calculator">11 - 16</gadget>
<output>-5</output>

<gadget id="calculator">8 + (-5)</gadget>
<output>3</output>

<result>3</result>