Conditional formatting formula

I have the following information in an Excel sheet:

Now I want to set conditional formatting for collumn B "Actual". If B3 is greater than or equal to A3 it should be green, if B3 is less than A3 it should be red. And so on for the following rows. 

I'm not sure how to set this up without having to set conditional formatting for every single cell. And since I have many more of these collumns and rows I really do not want to do that.

Is there a formula that I could use?

Thanks in advance for your help!