MasterPage Inherit class file

I have a Master page which needs to inherit from a class (MasterPage2.cs) stored inside "App_Web_yht1mma2" folder.

In the master page, I have set the code as:

<%@ Master Language="C#" AutoEventWireup="true" Inherits="MasterPage2,App_Web_yht1mma2" %>

When I debug this page, I receive the following error:

"ParserError
Description:An error occurred during the parsing of a resource required to servicethis request.Please review the following specific parse error detailsand modify your source file appropriately.
ParserErrorMessage:Couldnot load the assembly'App_Web_yht1mma2'.Make sure that it is compiled before accessing the page.
SourceError:
Line1: <%@MasterLanguage="C#"AutoEventWireup="true"Inherits="MasterPage2,App_Web_yht1mma2"%>
Line2: 
Line3: 
SourceFile:/MasterPage.master   Line:1"

Anyway I can correct this error please?