There are 60 colored balls in the bag, 6 of each color. When taking the ball blindfolded, it is necessary to ensure that there are three balls of the same color among the balls taken out, and at least how many balls must be taken out.
布袋中有60个彩球，每种颜色的球都有6个．蒙眼取球，要保证取出的球中有三个同色的球，至少要取出多少个球．
<gadget id="calculator">60 / 6</gadget>
<output>10</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<result>21</result>