FirstSortedValue() in set Analysis Issue

[#1]

Hi,

i have a table with City Dimension and want to know the top Vendor according to TRADE_VALUE and  distinct loaction_ID count of that Vendor ,

i am able to find the top vendor with help of firstSortedvalue().

now i want pass this function into set analysis and get the city wise distinct LOCATION_ID COUNT.

Below is the expression what i have written, but not getting the right result.

=count( {<VENDORSHORTNAME={"$(=FirstSortedValue(VENDORSHORTNAME,-Aggr(Sum(TRADE_VALUE),VENDORSHORTNAME,CITY)))"}>}DISTINCT LOCATIONID)

if you see the image closely the second record showing '0' but there are loaction_Id associated with that,

Kindly help

[MK_QSL]

Please provide sample data.