In this task, you are given a string of characters. You need to remove duplicate characters from the string if any, and return the resulting string.

Example Input: UdKQazyGqYGzbUzaazcJhE
Example Output: UdKQazyGqYbcJhE

Example Input: YMkiCvKjOpMYXaxHMGTZppIBGmpB
Example Output: YMkiCvKjOpXaxHGTZIBm

Example Input: DNdkHcHSKvkIJaZVDatbpCocRmM
Example Output:
DNdkHcSKvIJaZVtbpCoRmM