How to count num shops having stock 0 grouped at shop level?

[#1]

Raw Data:			Stock
	Field ITEM_PART_NUMBER		Shop A	Shop B	Shop C	Shop D
Items in substitution group 1 (PIVOT_ITEM_TYPE = 'SUBST'	Item 1	Substituting item	1	1	1	0
	Item 2	Substituded item	1	0	0	0
	Item 3	Substituded item	1	0	0	0
	Item 4	Substituded item	1	0	1	0
	Item 5	Substituded item	1	0	1	0
		Is Stock for all items in Substitution Group 1 aggregated At shop Level > 0 for previous day?	Yes as stock is 5	Yes as stock is 1	Yes as stock is 3	No as stock is 0
Thereby, KPI should return me count of shops = 1 having stock 0 grouped at substitution group 1 level and at each shop for the previous day
My question is how do I calculate a KPI which will return me only the count of shops having stock 0 grouped at substitution group 1 level and at each shop for the previous day?
I have tried the following possibilities but they are not working:
Aggr(sum({$<Date={">=$(=max(Date)-1)<$(=Date)"},Pivot_Item_Type = {'SUBST'}}QTY_STOCK)<=0, SHOP_CODE)
if(Aggr(sum({$<Date={">=$(=max(Date)-1)<$(=Date)"}>}QTY_STOCK), SHOP_CODE, ITEM_PART_NUMBER)=0, Count(DISTINCT SHOP_CODE),1)
if(Aggr(sum({$<Date={">=$(=max(Date)-1)<$(=Date)"}>}QTY_STOCK), ITEM_PART_NUMBER, SHOP_CODE)<=0,0,Count({$} SHOP_CODE))