There are 10 black and white chopsticks in the same bag, at least how many chopsticks must be taken out to ensure that there are two pairs of the same color.
有黑、白两种颜色的筷子各10只放在同一个袋子里，至少要拿出多少只才能保证有两双是同色的．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>