There are 49 people in class 31, 25 people ordered "Fairy Tale", and 35 people ordered "Story King". Among them, 18 people subscribed to both publications. How many people in this class have not subscribed to publications?
三1班共有49人，订《童话》的有25人，订《故事大王》的有35人．其中有18人两种刊物都订．这个班有几人没订刊物？
<gadget id="calculator">35 - 18</gadget>
<output>17</output>

<gadget id="calculator">25 + 17</gadget>
<output>42</output>

<gadget id="calculator">49 - 42</gadget>
<output>7</output>

<result>7</result>