Searching multiple columns

A spreadsheet has multiple 'paired' columns. Column "A" has part numbers with the supplier in column "B", column "C" has more (different) part numbers with the supplier in column "D", column "E" has more (different) part numbers with the supplier in column "F", etc. etc.

How would I find the supplier for a part number which could be (only once) in any of the coulmns apart from using IF NA# or IF Error?