10 pairs of shoes of different sizes are piled up together. If the shoes are randomly taken out so that at least two shoes can be matched into one pair, how many pairs of 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，试问需取出多少双鞋就能保证成功？
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<result>6</result>