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 Input:
FGhwvvBGIRusWiqUytlwJNHjLDB

Ex Output:
FGhwvBIRusWiqUytlJNHjLD

Ex Input:
gIbVlYsnmQJkeQqsrmuup

Ex Output:
gIbVlYsnmQJkeqrup

Ex Input:
urPUAGSMCdtYOaxOCmWXeaSdSZ

Ex Output:
urPUAGSMCdtYOaxmWXeZ