Proper way to declare variables for the global variables in C#

Here is the top part of my code in my <script runat="server">. Did I declare the private constate variables properly or do I need an underscore?

<script runat="server">
    private const int portraitHeight = 900;
    private const int portraitWidth = 700;

    private const int landscapeHeight = 700;
    private const int landscapeWidth = 900;

</script>