local communication application

I am looking for a professional team who can build a windows application which works on local network only (Please make sure this application MUST be disconnected from internet). I can give you conception about this app. Do you know Microsoft Team Chat? Features and UI designs can be very similar with Microsoft Team Chat, but of course, it has less features and simpler design. This application will work on Windows operating system and result should be exe files. Enjoy bidding, but your price and deadline should be not changed once you put bid. Important Note: I have 2 question to contact with serious candidates only. 1) 2 + 5 = ? 2) Do you have done any similar job before? Experienced candidates will be shortlisted.