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: gjroYPFlHUuyuFQeDOEpoLOWKZ
Example Output: gjroYPFlHUuyQeDOEpLWKZ

Example Input: QuMNYgXJKXvbSqRhUHAfsIAxqUYb
Example Output: QuMNYgXJKvbSqRhUHAfsIx

Example Input: GEBuvBzKGuwclisbkNYgnObhpT
Example Output:
GEBuvzKwclisbkNYgnOhpT