Xiaoming goes to the park every 6 days, and Xiaoli goes to the park every 9 days. Xiaoming and Xiaoli just met in the park today. How many days will it take before they meet again in the park?
小明每6天去一次公园，小丽每9天去一次公园，小明和小丽今天刚在公园见面，至少再过多少天，他们才会在公园再次见面？
<gadget id="calculator">2 * 3 * 3</gadget>
<output>18</output>

<result>18</result>