Take some numbers from the 2011 numbers of 1, 2, 3, ..., 2010, 2011, so that the sum of any two of them cannot be divisible by 7, then how many numbers can be taken at most.
从1，2，3，…，2010，2011这2011个数中取出若干个数，使其中任意两个数之和都不能被7整除，则最多可以取出多少个数．
<gadget id="calculator">288 * 2</gadget>
<output>576</output>

<gadget id="calculator">576 + 287 + 1</gadget>
<output>864</output>

<result>864</result>