Help me match two sets of data

Hey guys, hoping you can help with this simple problem

in my spreadsheet, from one of the data tables I have Column B with "invoice number" as a heading and Column E with "PO number" as a heading.

I need to match the contents of one of these two fields to column M, which has a mixture of the two.
ideally I'd like matched pairs to be filled in with a color, such as yellow


also I need to remove a "-" from all the contents of column M so it is in the same format as the contents of column B (E.g 201454 and 2014-54)


any help is appreciated.

many thanks