Set variables on a master page from content pages C#

studentID = System.Convert.ToInt32(Session[“sid”]);
studentFname = Session[“studentFname”].ToString();
studentMname = Session[“studentMname”].ToString();
studentLname = Session[“studentLname”].ToString();
char[] m = studentMname.ToCharArray();
studentMiddleInitial = m[0].ToString();

Label1.Text = studentID.ToString();
Label mpLogin = (Label)Master.FindControl(“usernamedisplay1″);
mpLogin.Text = studentFname + ” ” + studentMiddleInitial + ” ” + studentLname;