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.

[EX Q]: QmMvWNLmtqJPwqlAVTiTO
[EX A]: QmMvWNLtqJPwlAVTiO

[EX Q]: DNdkHcHSKvkIJaZVDatbpCocRmM
[EX A]: DNdkHcSKvIJaZVtbpCoRmM

[EX Q]: xpgVQicCOzavYkEiLbejlmU
[EX A]:
xpgVQicCOzavYkELbejlmU