Snowflake

using System;
using System.Text.RegularExpressions;

namespace Snowflake_01_18
{
    class Program
    {
        static void Main(string[] args)
        {
            string surface1 = Console.ReadLine();
            string mantle1 = Console.ReadLine();
            string core = Console.ReadLine();
            string mantle2 = Console.ReadLine();
            string surface2 = Console.ReadLine();

            string patternSurface = @"^[^A-Za-z0-9]+$";

            Match matchSurface1 = Regex.Match(surface1, patternSurface);
            Match matchSurface2 = Regex.Match(surface2, patternSurface);

            if (matchSurface1.Success == false || matchSurface2.Success == false)
            {
                Console.WriteLine("Invalid");
                return;
            }

            string patternMantle = @"^[0-9_]+$";

            Match matchMantle1 = Regex.Match(mantle1, patternMantle);
            Match matchMantle2 = Regex.Match(mantle2, patternMantle);

            if (matchMantle1.Success == false || matchMantle2.Success == false)
            {
                Console.WriteLine("Invalid");
                return;
            }

            string patternCore = @"^([^A-Za-z0-9]+)([0-9_]+)(?<core>[A-Za-z]+)([0-9_]+)([^A-Za-z0-9]+)$";

            Match matchCore = Regex.Match(core, patternCore);

            if (matchCore.Success == false)
            {
                Console.WriteLine("Invalid");
                return;
            }

            string validCore = matchCore.Groups["core"].ToString();

            Console.WriteLine("Valid");
            Console.WriteLine(validCore.Length);
        }
    }
}