The sum of two three-digit numbers \overline{abc} and \overline{def} is 1000. What is the maximum sum of the six numbers a+b+c+d+e+f?
两个三位数\overline{abc}与\overline{def}相加，和是1000，a+b+c+d+e+f这6个数字的和最大是多少．
<gadget id="calculator">9 + 9 + 10</gadget>
<output>28</output>

<result>28</result>