There are 20 socks of 6 colors with the same specification and size, and they are mixed together and put in a box. At least how many socks are taken out of the box to ensure that there are 3 pairs of socks.
有规格尺寸相同的6种颜色袜子各20只，混装在一起放在箱子里，从箱内至少取出多少只袜子才能保证有3双袜子．
<gadget id="calculator">6 + 1 + 1 + 1 + 2</gadget>
<output>11</output>

<result>11</result>