how can I do timercountdown start from a page to continue another page?

public partial class X: System.Web.UI.Page
    {
        public static int dt = 60;
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                if (Session["timerCount"] != null)
                {
                    dt = Convert.ToInt32(Session["timerCount"]);
                }
            }
        }

        protected void Timer1_Tick(object sender, EventArgs e)
        {
            Label1.Text = dt.ToString();
            dt -= 1;
        }

//Redirect to y.aspx
        protected void Button1_Click(object sender, EventArgs e)
        {
            //Save the current count value to session.
            Session["timerCount"] = dt;
            Response.Redirect("Y.aspx");
        }
    }

public partial class WebForm2 : System.Web.UI.Page
    {
        public static int dt1;

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                dt1 = Convert.ToInt32(Session["timerCount"]);
            }
        }

        protected void Timer1_Tick(object sender, EventArgs e)
        {
            Label1.Text = dt1.ToString();
            dt1 -= 1;
        }
        //Redirect back to X.aspx
        protected void Button1_Click(object sender, EventArgs e)
        {
            Session["timerCount"] = dt1;
            Response.Redirect("X.aspx");
        }
    }