There are 6 red, yellow, white, and blue cards in a box. There must be two cards of the same color that you want to take out, at least how many cards you need to take out.
在一个盒子里有红色、黄色、白色、蓝色的卡片各6张．要想拿出的卡片一定有两张是同色的，至少要拿出多少张卡片．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>