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]: czewqqMLGCBKQLVGDtng
[EX A]: czewqMLGCBKQVDtng

[EX Q]: PkHwzoXRUCvjtJtXOXbcvzDJ
[EX A]: PkHwzoXRUCvjtJObcD

[EX Q]: HEWadwrxiOMKskgGqlAALNHb
[EX A]:
HEWadwrxiOMKskgGqlALNb