Question 18
A 9-digit integer $\overline{abcdefghi}$ is formed using digits $1,2,3,4,5,6,7,8,9$ without repetition. If $A=\overline{abc}+\overline{bcd}+\overline{cde}+\overline{def}+\overline{efg}+\overline{fgh}+\overline{ghi}$, find the largest possible value of $A$.