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: ptUIcSNsiRtUWfLGkAOAf

A: ptUIcSNsiRWfLGkAO
****
Q: yMNwhyNBMbYIWExLOcTf

A: yMNwhBbYIWExLOcTf
****
Q: XvvFtcaSyJPwQyoifYBdQcxGECNG

A:
XvFtcaSyJPwQoifYBdxGECN
****