There are 6 red, yellow, blue, black, and purple balls in the bag. Take out as many balls as you want to ensure that at least 2 balls are of the same color.
袋子里有红、黄、蓝，黑，紫球各6个，任意拿出多少个球，才能保证至少有2个球颜色相等．
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<result>6</result>