using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

​

public class Program

{

    public static void Main()

    {

        if (IPAddress.TryParse("2a00:23c8:1d5b:bd01:5418:b773:e61f:caf", out _))

            Console.WriteLine("Valid");

    }

}