2

using System;
using System.Text.RegularExpressions;

namespace _2
{
    class Program
    {
        static void Main(string[] args)
        {
            Regex regex = new Regex(@"@#+([A-Z]{1}[a-z,A-Z,0-9]{4,}[A-Z]{1})@#+");
            int times = int.Parse(Console.ReadLine());

            for (int i = 0; i < times; i++)
            {
                var inputBarcode = Console.ReadLine();
                Match match = regex.Match(inputBarcode);

                if (match.Success)
                {
                    var validBarcode = match.Groups[1].Value;
                    var groupCode = GetBarcodeGroup(validBarcode);
                    Console.WriteLine($"Product group: {groupCode}");
                }
                else
                {
                    Console.WriteLine("Invalid barcode");
                }
            }
        }

        public static string GetBarcodeGroup(string barcode)
        {
            var groupCode = string.Empty;

            foreach (var letter in barcode)
            {
                if (char.IsNumber(letter))
                    groupCode += letter;
            }

            if (groupCode == "")
                groupCode = "00";

            return groupCode;
        }
    }
}