Java 1.0

package com.company.softuni;

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

public class Main3 {
    public static void main(String[] args) {
        Pattern pattern = Pattern.compile("^@#+[A-Z][a-zA-Z0-9]{4,}[A-Z]@#+$");
        Scanner scanner = new Scanner(System.in);

        int n = Integer.parseInt(scanner.nextLine());

        for (int i = 0; i < n; i++) {
            String line = scanner.nextLine();
            Matcher matcher = pattern.matcher(line);
            if (matcher.matches()) {
                line = line.replaceAll("\\D+","");
            }
            if (line.isEmpty()) {
                System.out.println("Product group: 00");
            } else {
                System.out.println("Product group: " + line);
            }
        }
    }
}