Choosing the available rating out of 3 rows in excel2016. with if ot if or??any suggestions?

I have a question regarding the excel.I have 3 columns of ratings for the equities that I am working on. For example column A (the equities) column B(S&P ratings)column C( Moodys Ratings) column D(Bloomberg Ratings) So for every equity, only one rating appears according to my data. I want to create a column E that includes the available rating across the row. To be more specific I want an order that said "IF S&P has rating show it, if not show the Moodys, if not show Bloomberg, if not show No Rating ". BTW I am using EXCEL 2016 Thanks