public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNextLine()) {
String str = sc.nextLine();
char[] charList = str.toCharArray();
Map<Character, Character> map = new LinkedHashMap<Character, Character>();
for (int i = charList.length - 1; i >=0; i--) {
char c = charList[i];
map.putIfAbsent(c, c);
}
for(Map.Entry<Character, Character> entry : map.entrySet()) {
System.out.print(entry.getKey());
}
}
}
}