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: vFRwzRsxhLqGSqvwxRkXiwetTLvzQ
Example Output: vFRwzsxhLqGSkXietTQ

Example Input: QuMNYgXJKXvbSqRhUHAfsIAxqUYb
Example Output: QuMNYgXJKvbSqRhUHAfsIx

Example Input: kjynMHqaVPzfJDTnXNHz
Example Output:
kjynMHqaVPzfJDTXN

