There are 50 people in a class who participate in the mathematics interest group and the Chinese interest group, and each person participates in at least one of them. It is known that 35 people participate in the mathematics interest group, and 5 people participate in both the mathematics interest group and the Chinese interest group. Ask to participate How many people are there in the language interest group?
某班有50人参加数学兴趣小组和语文兴趣小组，并且每人至少参加一项，已知参加数学兴趣小组的有35人，既参加数学兴趣小组又参加语文兴趣小组的有5人，问参加语文兴趣小组的有多少人？
<gadget id="calculator">5 - 35</gadget>
<output>-30</output>

<gadget id="calculator">50 + (-30)</gadget>
<output>20</output>

<result>20</result>