There are 10 black balls, 6 white balls, and 4 red balls in a pocket, at least how many balls are taken from it to ensure that there are red balls in it.
在一个口袋中有10个黑球、6个白球、4个红球，至少从中取多少个球，才能保证其中有红球．
<gadget id="calculator">10 + 6 + 1</gadget>
<output>17</output>

<result>17</result>