if (Request.Cookies["LastVisit"] == null)
                {
                   Response.Cookies.Add(new HttpCookie("LastVisit"));
                   Response.Cookies["LastVisit"].Value = DateTime.Now.ToString();

                   
                    Session["label"] = "this is the first time you login!";
                }
                else
                {
                    string str=Request.Cookies["LastVisit"].Value.ToString();
                  
                    Session["label"] = str;
                    Response.Cookies["LastVisit"].Value = DateTime.Now.ToString();
                }