count of summarize

Question:
The TableMain at the bottom returns a table with data correctly.

VAR TableMain =
FILTER (
SUMMARIZE (
Table1,
Table1[Field1],
Table2[Field1],
Table1[Field2],
"Count", DISTINCTCOUNT ( Table3[Field2] ),
"Total Sales", [MyMeasure]
),
[Total Sales] > 10
)

Question:
How do I do a sum (In a separate measure) for the column "Count" in table TableMain ?

The following count dax does not work:
CALCULATE(SUM(Mandates[Count]))

Thank you