10 pairs of shoes of different sizes are stacked together. If the shoes are randomly taken out so that at least two shoes can be matched into one pair, how many shoes need to be taken out to ensure success?
10双不同尺码的鞋子堆在一起，若随意地取出鞋来，并使其至少有两只鞋可以配成一双，试问需取出多少只鞋就能保证成功？
<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<result>11</result>