I've got a worksheet with a column of data like A:

A B
4 Match
5 Mismatch
4 Match
4 Mismatch
6 Match
2 Mismatch
1 Mismatch
6 Match

I'm trying to find a formula or a macro that could give me an output
like in column B....The big problem is that i need to find only single pairs
of data (E.G: the first two "4" are matching, the third one is mismatching
because there isn't another one in column A). I've tried with countif and
offset but they doesn't work.

Someone could give me an hint on a formula or a macro?
Thanks for your time.

Live Long and Prosper,
Xerses from Home.