Hi - Please help if you know how to address the following required validation
in single rule. I would like to prevent duplicates and limit the text entry
to 100 characters. Is there a way to do this?

Assuming that my range is in C71:C100 I have the following but the length
part is not working right?
=AND(COUNTIF($C$71:$C$100,C71)=1,LEN(C71<151))

Any help would be appreciated! Thanks