Given a string S. Your task is to remove all duplicates characters from the string S

NOTE:
1.) Order of characters in output string should be same as given in input string.
2.) String S contains only lowercase characters ['a'-'z'].

input:
Input contain a single string S.

Output:
Print the string S with no any duplicate characters.

Constraints:
Test Files 1 to 5:
1<=|S|<=100
Test Files 6 to 10:
1<=|S|<=100000

Sample Output #1
hacker

Sample Output #1
hacker

Sample Input #2
hackerearth

Sample Output #2
hackert

Sample Input #3
programming

Sample Output #3
progamin