Need Help with this DAX calculation

I have figured out however i am unsure if this is the most optimal way 

happy for someone to suggest better way 

countx(
    filter(
        summarize(
                test,
                test[CRM ID],
                test[CRM Close Date],
                "_1",
                countrows(
                            filter(
                                    test,
                                    not isblank(test[Task Close Date])
                            )
                ),
                "_2",
                countrows(test)
        ),
        isblank(test[CRM Close Date]) && [_1]=[_2]
    ),
    test[CRM ID]
)