The teacher gave two thinking questions to the whole class. As a result, 26 people got the first question right, 18 people got the second question wrong, and 12 people got both questions right. Then, they got both questions wrong. How many people are there.
教师出了两道思考题给全班同学做，结果做对第一题的有26人，做错第二题的有18人，两题都做对的有12人，那么两题都做错的有多少人．
<gadget id="calculator">26 - 12</gadget>
<output>14</output>

<gadget id="calculator">18 - 14</gadget>
<output>4</output>

<result>4</result>