Exit code

Professor X got lost in a maze of an ancient tomb in Egypt. While he was finding the way to escape, he got a message of the tomb builders on the old walls: - The code to open the exit door is the sequence C of n digits formed c1..cn (ci∈[0,9] ). - For every sequence C, combining with the given integers A,B, call: - h0=0 - hi=(hi-1×A+ci) mod B - The smallest sequence C (in lexicological order)