The Easiest Problem Is This One Solution:

import java.util.Arrays;
import java.util.Scanner;

public class Kattis {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        Scanner sc = new Scanner(System.in);
        for (int curr = sc.nextInt(); curr != 0; curr = sc.nextInt()) {
            int match = sumOfDigits(curr);
            int count = 11;
            for(; sumOfDigits(count * curr) != match;count++);
            sb.append(count + System.lineSeparator());
        }
        System.out.println(sb);
    }
    public static int sumOfDigits(int num) {
        return Arrays.stream(Integer.toString(num).split("")).mapToInt(Integer::parseInt).sum();
    }
}