Jedi Test

Quigon and Obi Wan are really impressed with your ability since you helped them escape the assassins sent by Senator Palpatine. They feel that you are an ideal Jedi candidate. However to confirm their instincts, they need to test you one last time. To prove yourself, you are given two integers $a$ and $b$. Find the number of integers between a and b whose sum of digits is divisible by $x$ and prod