There are 46 people in class 31, 25 of them subscribed to "Youth Science", 22 people subscribed to "Youth Literature and Art", and 18 people subscribed to both publications. How many people do not subscribe to either publication?
三1班有46人，其中25人订阅了《少年科学》，22人订阅了《少年文艺》，有18人两种刊物都订阅了．有多少人两种刊物都没有订阅？
<gadget id="calculator">22 - 18</gadget>
<output>4</output>

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

<gadget id="calculator">46 - 29</gadget>
<output>17</output>

<result>17</result>