using System;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

        var a=Convert.ToInt64(DateTime.Now.ToString("yyyyMMdd") + GenerateRNG(10000000000, 99999999999).ToString());

        Console.WriteLine(a);

    }

    public static long GenerateRNG(long min, long max)

        {

            if (min > max) throw new ArgumentOutOfRangeException(nameof(min));

            if (min == max) return min;

            using (var rng = new RNGCryptoServiceProvider())

            {

                var data = new byte[4];

                rng.GetBytes(data);

                long generatedValue = Math.Abs(BitConverter.ToInt32(data, startIndex: 0));

                long diff = max - min;

                long mod = generatedValue % diff;

                long normalizedNumber = min + mod;

                return normalizedNumber;

            }

        }

}