How can I approach for this number theory problem ? [Problem Link](http:// https://codeforces.com/contest/1070/problem/A)
A. Find a Number time limit per test3 seconds memory limit per test256 megabytes inputstandard input outputstandard output
You are given two positive integers d and s. Find minimal positive integer n which is divisible by d and has sum of digits equal to s.
Input The first line contains two positive integers d and s (1≤d≤500,1≤s≤5000) separated by space.
Output Print the required number or -1 if it doesn't exist.
Examples input 13 50 output 699998
input 61 2 output 1000000000000000000000000000001
input 15 50 output -1