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.

Example Input: cVdvXEQiSKllmgVBHwPRZPNMQfiQe
Example Output: cVdvXEQiSKlmgBHwPRZNMfe

Example Input: ZpBNToFTMLvOZFoGObBhCXaGqCf
Example Output: ZpBNToFMLvOGbhCXaqf

Example Input: IpFBHqaAeWEXwHnzkFhZQTlS
Example Output:
IpFBHqaAeWEXwnzkhZQTlS