I was solving a URI question about finding the minor number that's multiple of a divisor given.
I found this problem:

Dividend: 4?3?771?2?166??56??357?2223

Divisor: 909

I need to fill my dividend '?' with numbers, and find the lowest possibly number that result in a remainder = 0, without modifying the fixed numbers.

I tried some brute force with Python but i didn't get a fast algorithm.

How can i do that?