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: OOwybftCNaoQnrkYlqucDuGvBwiB

A: OwybftCNaoQnrkYlqucDGvBi
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Q: ILvmKIZpqZdtVJZXTtayEzfrLpFew

A: ILvmKZpqdtVJXTayEzfrFew
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Q: QuMNYgXJKXvbSqRhUHAfsIAxqUYb

A:
QuMNYgXJKvbSqRhUHAfsIx
****