There are 40 students in class 3 and 2, 25 of them have subscribed to "Youth Science", 23 have subscribed to "Youth Literature and Art", and 19 have subscribed to both publications. So, how many people have never subscribed to both publications?
三2班有40个同学，其中有25人订阅了《少年科学》，23人订阅了《少年文艺》，有19人两种刊物都订阅了，那么，有多少人两种刊物都未曾订阅？
<gadget id="calculator">23 - 19</gadget>
<output>4</output>

<gadget id="calculator">25 + 4</gadget>
<output>29</output>

<gadget id="calculator">40 - 29</gadget>
<output>11</output>

<result>11</result>