There are 5 red balls, 5 yellow balls, and 5 white balls in the pocket. At least how many balls must be drawn to ensure that there are 3 balls of different colors.
口袋里有红球、黄球、白球各5个，至少要摸出多少个球，才能保证有3种不同颜色的球．
<gadget id="calculator">5 + 5 + 1</gadget>
<output>11</output>

<result>11</result>