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.

nCTfNLTHhSZkAhJRYGwESheWQVNZQU
nCTfNLHhSZkAJRYGwEeWQVU

wghwXLflnbkSbtCbFosA
wghXLflnbkStCFosA

pfnVbGKENymodcvWtfDkdCzPhO

pfnVbGKENymodcvWtDkCzPhO