Format the Above Cell

[PostTIT]

Alright, well this may sound simple to some.

I have a spreadsheet that has minute-by-minute data values recorded from each day throughout a given year.
Column A has the date in dd/MM/yyyy format.
Column B has the time in hh:mm:ss format.

This should be 527040 values, however I don't have that amount of values.

What I'm wanting to do is, in column B, highlight any cells that repeat the value from the cell above. So if a minute value repeats twice (or more) in succession it is highlighted.

Some form of conditional formatting I suppose.

I've tried a few things such as:

=IF(A2=A1,1,0)

and other things but they didn't work - maybe I did them wrong I'm not sure.

Any help would be great.

 

[PostTIT]

If it makes a difference, I found another - manual - way to go about what I was trying to do so I don't need a solution to this problem.
However, I'm sure a solution would be beneficial to others and maybe to myself in the future.