There are 6 socks of 5 kinds of red, yellow, blue, black, and white in a cloth bag. If you are blindfolded and let you take socks in the bag, how many socks can you take at least to ensure that you can get two socks? Pairs of socks of the same color.
在一只布袋里放着红色、黄色、蓝色、黑色、白色5种袜子各6只，如果把你的眼睛蒙起来，让你在袋子中拿袜子，至少拿多少只才可以保证拿到两双颜色相同的袜子．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<result>16</result>