Put 10 balls of red, yellow, blue, and white into a box, at least how many balls must be drawn to ensure that 3 balls are of the same color.
把红、黄、蓝、白四种颜色的球各10个放到一个盒子里，至少要摸出多少个球，保证有3个球是同色的．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<result>9</result>