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: MlDKuBkwRGNIptTnWEQKo
Example Output: MlDKuBkwRGNIptTnWEQo

Example Input: wyfKgihlkYvlIOXsZWHlnOuaYJSnmW
Example Output: wyfKgihlkYvIOXsZWHnuaJSm

Example Input: UjFUhwNrJXIGhoygEiQJAEub
Example Output:
UjFhwNrJXIGoygEiQAub