Excel Formula Question?

I want to use a vlookup formula in excel, but I want to make it so that if the value returned is N/A for any given cell to be another value (the cell adjacent to the formula). For example, if cell A1 is the anchor and the vlookup is in cell B1, if the value retuned is N/A I want it to show A1 instead. So I think I need some sort of if statement here, but I'm unsure how to do it.