There are 122 students in the fifth grade who have taken the Chinese and mathematics exams, and each of them has achieved excellent results in at least one homework. Among them, there are 65 people who are excellent in Chinese, 87 people who are excellent in mathematics, and how many people are excellent in both Chinese and mathematics.
五年级有122名学生参加语文、数学考试，每人至少有一门功课取得优秀成绩．其中语文成绩优秀的有65人，数学优秀的有87人，语文、数学都优秀的有多少人．
<gadget id="calculator">87 - 122</gadget>
<output>-35</output>

<gadget id="calculator">65 + (-35)</gadget>
<output>30</output>

<result>30</result>