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.
--------
Question: BOPbKEiInAGqyixJWhkPkbCGMCxjj

Answer: BOPbKEiInAGqyxJWhkCMj


Question: PgnuLHMWcjJVzGyJelrh

Answer: PgnuLHMWcjJVzGyelrh


Question: nzUqqilKVDvdWlSqkjyLss

Answer:
nzUqilKVDvdWSkjyLs