There are 5 red and 5 blue balls of the same size in a box. There must be 3 balls of the same color if you want to draw out, and how many balls must be drawn at least once.
盒子里有同样大小的红球和蓝球各5个．要想摸出的球一定有3个同色的，一次最少要摸出多少个球．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>