using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Old Timestap >>" + getDBTimeStamp("1698170707040") +"");

        Console.WriteLine("Old Timestap >>" +getDBTimeStamp("1698173824000") +"");

    }

    public static String getDBTimeStamp(String unixTimeStamp)

        {

            string ContactSeqno = unixTimeStamp;

            DateTime dateSync = ConvertFromUnixTimestamp(double.Parse(unixTimeStamp) / 1000);

            Console.WriteLine( "New timestamp>>" + (dateSync.Hour == 0 ? "24" : dateSync.Hour + "") + (dateSync.Minute == 0 ? "00" : dateSync.Minute < 10 ? "0" + dateSync.Minute : dateSync.Minute +"")  + "" + ( dateSync.Second == 0 ? "00" : dateSync.Second < 10 ? "0" + dateSync.Second : dateSync.Second +"") + "" + (dateSync.Millisecond == 0 ? "00" : dateSync.Millisecond < 10 ? "0" + dateSync.Millisecond : dateSync.Millisecond +""));

            ContactSeqno = dateSync.Hour == 0 ? "24" : dateSync.Hour + "" + dateSync.Minute + "" + dateSync.Second + "" + dateSync.Millisecond + "";

            return ContactSeqno;

        }

        public static DateTime ConvertFromUnixTimestamp(double timestamp)

        {

            DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);

            return origin.AddSeconds(timestamp);

        }

}