There are several small balls of 4 different colors in the cloth bag, and the minimum number of small balls taken out can ensure that there must be 2 small balls of the same color.
布袋里有4种不同颜色的小球若干个，最少取出多少个小球就能保证其中一定有2个小球的颜色相同．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>