1 ball can be exchanged for 5 shuttlecocks, 1 shuttlecock can be exchanged for 2 table tennis balls, and how many table tennis balls can be exchanged for 3 leather balls.
1个皮球可以换5个羽毛球，一个羽毛球可以换2个乒乓球，3个皮球可以换多少个乒乓球．
<gadget id="calculator">2 * 5 * 3</gadget>
<output>30</output>

<result>30</result>