Java Hayvan Numbers

import java.util.Scanner;


public class HayvanNumbers {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int sum = input.nextInt();
        int diff = input.nextInt();
        int resultCount = 0;

        for (int n1 = 555; n1 <= 999; n1++) {
            int n2 = n1 + diff;
            int n3 = n2 + diff;
            String number = "" + n1 + n2 + n3;

            if(isAllowed(number)&& (calculateSum(n1) + calculateSum(n2) + calculateSum(n3) == sum)) {
                System.out.printf("%d%d%d", n1, n2, n3);
                resultCount++;
                System.out.println(number);
            }
        }
        if (resultCount == 0) {

        }
    }
    public static int calculateSum (int n) {
        int sum = 0;

        int n1 = n % 10;
        n = n / 10;
        int n2 = n % 10;
        n = n / 10;
        int n3 = n % 10;

        sum = n1 + n2 + n3;
        return sum;
    }
    public static boolean isAllowed(String n) {
        boolean isAllowed = true;
        char[] numbers = n.toCharArray();

        for (char c : numbers) {
            if (c != '5' && c != '6' && c != '7' && c != '8' && c!= '9') {
                isAllowed = false;
                return isAllowed;
            }
        }
        return isAllowed;
    }
}