There are 10 red, white and blue balls in a bag, at least how many balls can be taken out to ensure that there are 3 balls of the same color.
一个袋子里有红、白、蓝三种颜色的球各10个，至少拿出多少球才能保证有3个颜色的球是同色．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<result>7</result>