Find the Count of Random Serial Numbers from response data and Find Duplicate Numbers from Response data in Jmeter

i have query on how to find the count of the random serial numbers which are getting in Jmeter response and find the duplicate serial numbers from the generated serial numbers.

Jmeter Response Data:

C5FV55WGJC

C5FX1N257P

C5G0F54VPN

C5G77R09CD

C5G7L33Y2T

C5G7X7NWYF

C5FX1N257P

From above response data i need to count the numbers and find the duplicate numbers from response.

can you please help me out on this. Thanks in advance!