Calculating Overtime

Hello,
This is my first post here, so please go easy on a new guy like myself. I was wondering if anyone could help me fix my payroll employee time sheet and overtime. Before you jump the gun and tell me to try SEARCH, I've searched through other threads but haven't found anything that matches my criteria exactly.

Here's what I would like to do:
One column should have the total number of hours. The next column should be hours out of 40. So if the person worked 40 hours or more this column would say 40. The next column would calculate overtime (anymore than 40 hours).

I hope I explained it well enough. I've attached a file to illustrate the basic layout. Any help would be greatly appreciated. Thanks in advance to any who helps me out.