creating a unique key for non and duplicated record ids

[Manexcel]

I have a long list (several thousand) of record ids - see below. Each record id is associated to a name of an individual who belong to "n" groups for very good reasons. Hence a record ID can be replicated many times because the individuals belong to many groups.

I wish to create a unique key for each record id and that "duplicate" record ids also have a unique key.

Is there a formula that can create these unique keys?

I trust the above makes sense and I thank you in anticipation.

Col A
7612354
10197609
7217579
9242430
9242430
3043762
7942672
7942672
7942672
6840337
9530460
3101304
3127478
7416970
7416970
10459476
5606020
5606020
5606020
5606020
5

560620
5606020
5606020
5606020
5606020​

5606020

etc

 

[Fennek]

Hello,

B1: =A1 & "-" & countif($A$1:A1;A1)

regards

 

[Manexcel]

Thank you very much for your quick response. All worked ok. This can now be closed.