Now there are several numbers 8, 9, 10, 11, ..., 14, delete two numbers from the middle each time, and add the sum of these two numbers at the same time, until there is only one number left at the end, then the last number how many.
现在有8，9，10，11，…，14几个数字，每次从中间删去两个数字，并同时添加进去这两个数字的和，直到最后只剩下一个数字，那么最后这个数字是多少．
<gadget id="calculator">8 + 9 + 10 + 11 + 12 + 13 + 14</gadget>
<output>77</output>

<result>77</result>