Question 99
Let $s(a)$ denote the sum of digits of a given positive integer $a$. The sequence $a_{1}, a_{2}, \ldots, a_{n}, \ldots$ of positive integers is such that $a_{n+1} = a_{n} + s(a_{n})$ for each positive integer $n$. Find the greatest possible $n$ for which it is possible to have $a_{n} = 2008$.