This is a strange numeral system which consists of 256 elements, represented by combinations of letters. 0 - 'A'; 1 - 'B'; ... 234 - "iA"; 235 - "iB"; ... 255 - "iV" The code converts a decimal (decimal based numeral system) to a Kaspichan Numeral system (strange system)

Strange Numeral System

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace KaspichanNumbers
{
class KaspichanNumbers
{
static void Main()
{
    ulong InputNumber = ulong.Parse(Console.ReadLine());
    List<string> Kaspichan = new List<string>();
    List<string> OutputNumber = new List<string>();

    for (char i = 'A'; i <= 'Z'; i++)
    {
        Kaspichan.Add(i.ToString());
    }
    char EndChar = 'Z';
    for (char i = 'a'; i <= 'i'; i++)
    {
        if (i == 'i')
        {
            EndChar = 'V';
        }
        for (char j = 'A'; j <= EndChar; j++)
        {
            Kaspichan.Add(i.ToString() + j.ToString());
        }
    }

    while (InputNumber > 0)
    {
        ulong Remainder = InputNumber % 256;
        InputNumber /= 256;
        OutputNumber.Add(Kaspichan[(int)Remainder]);
    }

    OutputNumber.Reverse();

    foreach (var number in OutputNumber)
    {
        Console.Write(number);
    }
}
}
}