There are 5 red balls and 5 yellow balls of the same size in a bottle. There must be 2 balls of the same color if you want to draw out the balls, at least how many balls must be drawn out.
瓶子里有同样大小的红球和黄球各5个．要想摸出的球一定有2个同色的，最少要摸出多少个球．
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<result>3</result>