using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(NSB60.Convert(19840416092000));

        Console.WriteLine(NSB60.Revert("75eWicdk"));

    }

    internal static class NSB60

    {

        static long  ibase = 60;

​

        static string[] Tab60 = {

            "0","1","2","3","4","5","6","7","8","9",

            "a","b","c","d","e","f","g","h","i","j",

            "k","l","m","n","o","p","r","s","t","u",

            "v","w","x","y","z","A","B","C","D","E",

            "F","G","H","I","J","K","L","M","N","O",

            "P","R","S","T","U","V","W","X","Y","Z"

        };

​

        public static string Convert(long Value)

        {

            string result = "";

            while (Value > 0)

            {

                result+=Tab60[Value%ibase];

                Value=Value/ibase;

            }

            return StringInvert(result);

        }

​

​

        public static long Revert(string Value)

        {            

            long result = 0;

            Value=StringInvert(Value);

            int x = 0;

            string s="";

            while (x<Value.Length)

            {

                s = Value[x].ToString();

                result+=Array.IndexOf(Tab60,s)*(long)Math.Pow(60,x);

                x++;

            }

            return result;

        }

​

​

​

        public static string StringInvert(string str)

        {

            string lStr = "";

            while (str.Length>0)

            {

                lStr += str[str.Length-1];

                str=str.Remove(str.Length-1);

            }

            return lStr;

        }

    }

}