Ranking with Filters

Hi  Team,

I must confess I am still a newbie to DAX,

I have a Table with which I wish to rank Visit Time based on Date and Staff ID. It looks like this:

I will like to have a Calculated Column that Ranks the Visit Time by Visit Date & StaffNo. Like this:

What Formula can I use for the calculated column.

You can view the above data in excel format here: https://drive.google.com/file/d/0Byxc8IzPhZ5-YUx3MnBlR0FjZ1U/view?usp=sharing

Thank you.

Ashish_Mathur v-ljerr-msft