There are 52 students in Class 5 and 4, 38 of them like to watch "Where are we going, Dad?" and 27 of them like to watch "Big Variety Show". There are 20 people who like to watch both programs. How many people don't like to watch both programs?
五4班共有52名学生，喜欢看"爸爸去哪儿"节目的有38人，喜欢看"百变大咖秀"的有27人．两个节目都喜欢看的有20人．两个节目都不喜欢看的有几人？
<gadget id="calculator">27 - 20</gadget>
<output>7</output>

<gadget id="calculator">38 + 7</gadget>
<output>45</output>

<gadget id="calculator">52 - 45</gadget>
<output>7</output>

<result>7</result>