There are 34 students in Class 4, 17 of them are fond of table tennis, 14 are fond of swimming, and 4 are fond of both table tennis and swimming. So, how many people don't like both.
四1班有学生34人，其中爱好乒乓的有17人，爱好游泳的14人，既爱好乒乓又爱好游泳的4人．那么，两样都不爱好的有多少人．
<gadget id="calculator">14 - 4</gadget>
<output>10</output>

<gadget id="calculator">17 + 10</gadget>
<output>27</output>

<gadget id="calculator">34 - 27</gadget>
<output>7</output>

<result>7</result>