A box contains balls of the same size but different colors. There are 10 balls in each of the four colors of red, yellow, green, and white. Ask the minimum number of balls that must be drawn to ensure that there are 5 balls of the same color.
一个盒子里装有大小相同但颜色不同的球，分别有红、黄、绿、白四种颜色的球各10个，问最少要摸出多少个球才能保证有5个同色的．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">16 + 1</gadget>
<output>17</output>

<result>17</result>