using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

var random = new Random();

var result = new string(

    Enumerable.Repeat(chars, 30800)

              .Select(s => s[random.Next(s.Length)])

              .ToArray());

        Console.WriteLine(result);

    }

}