There are 10 white gloves and 10 black gloves in the bag, at least how many gloves can be taken out to ensure that there is a pair of black gloves and a pair of white gloves.
袋子里有10只白手套和10只黑手套，至少拿出多少只手套才能保证有一双黑手套和一双白手套．
<gadget id="calculator">10 + 2</gadget>
<output>12</output>

<result>12</result>