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: FsDiXVqAymUcNSwuyNjb
Example Output: FsDiXVqAymUcNSwujb

Example Input: gIbVlYsnmQJkeQqsrmuup
Example Output: gIbVlYsnmQJkeqrup

Example Input: ysbPVZPTUdvimMzWIKPfyYIVrpGq
Example Output:
ysbPVZTUdvimMzWIKfYrpGq