Four IF statements to combine

Hi all,

Sat with since lunch and couldn't work out how to make formula working. I need to write IF statement with 4 criteria, or at least I think IF will do the trick. It would be difficult and not very visual to describe my question here, therefore I have attached a dummy workbook with the comments. Basically I have got 2 values in 2 columns. Next 2 columns will hold letter "x". There are 4 possible variations how "x" will appear in those two columns: first, second, both or none. So depending where the "x" is, I need to return one of the 2 values. Any ideas?

Thanks guys!