conditional formatting for not duplicate rows.

[kang]

I have A, B columns,
and I want to do conditional-formatting for rows whose A is the same and
B is not the same.
I mean
X 1
Y 2
Z 3
Z 3
Y 1
X 2
because for all rows B column for X have different (1,2), so i want to
highlight them.
on the other hand,
for Z's B column have the same values(3) so I want them to be intact.

Am I clear?

 

[Max]

One way

Assume data within A1:B100

Select A1:B100 (with A1 active), then apply CF using Formula Is:
=SUMPRODUCT(($A$1:$A$100=$A1)*($B$1:$B$100=$B1))<2
Format to taste, ok out.