Compare two custom fields with native field

Hi Martin,
How to Compare Multiple date fields and find the latest date among them and output string based on latest date. Example: PCR received date, PCR responded date and Agreed requirements date .
if PCR recevied date is latest date compared to other date fields then i want status to be ‘PCR received’.
if PCR responded is latest date compared to other dates than i want status as ‘PCR Responded’.
if Agreed requirements date is latest compared to other dates than i want status as ‘Reqs Agreed’
Please assist