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: DlmAHZNmehvEvkQpzINROIAZ
Example Output: DlmAHZNehvEkQpzIRO

Example Input: gDIPvWmlixrglCwaYyamVpPrGN
Example Output: gDIPvWmlixrCwaYyVpGN

Example Input: ysbPVZPTUdvimMzWIKPfyYIVrpGq
Example Output:
ysbPVZTUdvimMzWIKfYrpGq

