SSAS - MDX - Last child from distinct count

I have a measure which is created as Distinct Count on column (Surrogate_Part_ID). It is OK, but I need in row "Sum" a value = 255 147, because now is returned distinct count for two days (21.10. and 22.10.).

So is it possible create calculated aggregation something as LastChild from distinct count? [Measure].[Distinct Count Parts].[LastChild] - is it possible?