Create procedure with Output Parameter and display in Label using C# in ASP.Net

Hi! I used below cod;, but I couldn't get Id:

create procedure GetIdGost
@Name varchar(25),
@IdGost int output
as
declare @id int,@d int,@i int 
select @id = max(Id) from TblFirst
select @d = max(Id) from TblSecond
if isnull(@id,0) = 0 and isnull(@d,0) = 0
begin
set @i = 1
select @i
end
else if (isnull(@id,0) > isnull(@d,0))
set @i = @id + 1
else if (isnull(@id,0) < isnull(@d,0))
set @i = @d + 1
begin
set nocount on;
insert into  TblPeople(Id, Name)values(@i, @Name)
set @IdGost = scope_identity()
return @IdGost
end

        protected void AddGost_Click(object sender, EventArgs e)
        {
           addgost(Name.Text);    
        }

        public bool addgost(string name)
        {
            SqlConnection con = new SqlConnection(UserData);
            SqlCommand cmd = con.CreateCommand();
            string sql = "exec GetIdGost '" + name.ToString() + "'";
            cmd.CommandText = sql;
            con.Open();
            try
            {
                cmd.BeginExecuteNonQuery();

                IdText.Text = cmd.Parameters["@Idg"].Value.ToString();
            }
            catch { }
            con.Close();
            return true;
        }