There are 7 red balls and 9 white balls. They are mixed and put into a cloth bag. How many balls can be drawn at least once to ensure that the two balls are of different colors?
有红球7个，白球9个，混合后放到一个布袋里，问一次至少摸出多少个，就能保证两种球不同色？
<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<result>10</result>