Excel 2013 if statement with multiple and statements

I've been looking at other examples but I'm not sure how to apply them. I've gone through some trial and error and either get "Yes" when I know I shouldn't (not all four fields have the prerequisite "Yes" in them) or I get an error message. The code I have is just for U4 and V4 but I would like to make it for four cells (W4 and X4, also).

Essentially,

    =IF(U4="Yes" AND  (V4 ="Yes"), "Complete", "No")