There are 19 people in class 4<1>. According to the statistics of the class meeting: 15 people finished their Chinese homework in the morning, 18 people finished their math homework, and there were no students who did not finish both Chinese and math. Please do the math: How many students in our class have finished their Chinese and math homework in the morning?
四＜1＞班有19人．根据班会统计：上午做完语文作业的有15人，做完数学作业的有18人，语文、数学都没有做完的同学没有．请你算算看：我们班上午语文、数学作业都做完的同学有多少人？
<gadget id="calculator">18 - 19</gadget>
<output>-1</output>

<gadget id="calculator">15 + (-1)</gadget>
<output>14</output>

<result>14</result>