Functions ASP.NET C#

<%@Page Language="C#" %>
<script runat="server">

    public string hello()
    {
        string msg = "Hello World<br />\n";
        return (msg);
    }

    public int add()
    {
        int x= 10;
        int y = 20;
    return (x + y);
    }
</script>

<% Response.Write(hello()); %>
<% Response.Write(add()); %>