Max Date in List Box?

[#1]

I used an expression to get max date from my timestamp:

COUNT(IF(AGGR(NODISTINCT MAX(INSTC_CAPTR_TSTMP),COM_BUSN_ID)=INSTC_CAPTR_TSTMP,COMU_BUSN_ID))

I created a List Box from the above expression which contains all my max timestamp dates but they are listed in the List Box as follows:

7/23/2012 12:00:57AM      0

7/23/2012 12:04:33AM      0

7/24/2012 12:18:22AM      1

7/24/2012 9:22:27AM        0

7/24/2012 9:36:33AM        1

I want to display in the List Box one value of 'Y' for all the records above where there's a '1' but how do you do that?

[#2]

The easiest way would be to write it in the expression in the form IF(X=X,'Y'). Here is an example.