A bag contains 20 green socks, 30 blue socks, and 40 white socks, all of the same size. How many socks can be found without looking with eyes, so as to ensure that there is at least one pair of socks in the drawn socks. (Two socks of the same color are a pair)
一个袋子中有20只绿袜子、30只蓝袜子，40只白袜子，大小都一样．不用眼睛看，至少摸出多少只袜子，才能保证摸出的袜子中至少有1双袜子．(颜色相同的两只袜子为一双)
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>