Put 4 balls of red, yellow, and white in a box, at least how many balls are taken out to ensure that 4 balls of the same color are taken.
把红、黄、白三种颜色的球各4个，放在一个盒子里，至少取出多少个球，可以保证取到4个颜色相同的球．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<result>10</result>