MS Access Count duplicate records for each value

Hello,

I am new to Access and need to do a simple task that can be done in Excel - to count duplicate records for each ID that can be simply done in Excel with a pivot table. I need to use Access rather tan Excel because I have millions or the row entries. I really hope one of the Access pros can help me.

My data in access table looks like below where there are two columns: (1) UniqueID is a primary key and has unique records and (2) the User ID column has duplicate records

UniqueID column
1
2
3
4
5
6
7
8
9
10

User ID column
345
345
980
234
980
234
345
876
980
980

I need the data look like below and to perform the following actions: (1) to deduplicate User ID column and then (2) to count the number of records in UniqueID column per unique/deduplicated User IDs and insert the count in an additional column.

User ID column
345
980
234
876

Count of UniqueID
3
4
2
1

Thank you in advance!