A class of fifth grade students participated in the red scarf traffic post. Every group of 9 people has no surplus; every group of 6 people has no surplus. How many people may there be in a fifth grade class?
五年级一班同学参加红领巾交通岗．每9人一组，没有剩余；每6人一组，也没有剩余．五年级一班可能有多少人？
<gadget id="calculator">2 * 3 * 3</gadget>
<output>18</output>

<result>18</result>