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.

Q: nzUqqilKVDvdWlSqkjyLss

A: nzUqilKVDvdWSkjyLs
****
Q: pfnVbGKENymodcvWtfDkdCzPhO

A: pfnVbGKENymodcvWtDkCzPhO
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Q: YMkiCvKjOpMYXaxHMGTZppIBGmpB

A:
YMkiCvKjOpXaxHGTZIBm
****