02. Fancy Barcodes

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PyrvaZadacha {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String regex = "@#+(?<text>[A-Z][A-Za-z\\d]{4,}[A-Z])@#+";
        Pattern pattern = Pattern.compile(regex);
        int n = Integer.parseInt(scanner.nextLine());
                for (int i = 0; i < n; i++) {
            String message = scanner.nextLine();
            Matcher matcher = pattern.matcher(message);
            if(matcher.find()) {
                String textToCheck = matcher.group("text");
                StringBuilder sb = new StringBuilder();
                for (int j = 0; j < textToCheck.length(); j++) {
                    char c = textToCheck.charAt(j);
                    if (c >= 48 && c <= 57) {
                        sb.append(c);
                    }
                }
                String productGroup = sb.toString();
                if (productGroup.equals("")) {
                    System.out.println("Product group: 00");
                } else {
                    System.out.println(String.format("Product group: %s", productGroup));
                }
            } else{
                System.out.println("Invalid barcode");
            }
        }
    }
}