import java.util.ArrayList;
import java.util.Scanner;
public class Main{
public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int nextInt = scanner.nextInt(); String s = String.valueOf(nextInt); char[] chars = s.toCharArray(); ArrayList arrayList = new ArrayList(); StringBuilder stringBuilder = new StringBuilder(); for (int i = chars.length - 1; i >= 0; i--) { if (!arrayList.contains(chars[i])) { arrayList.add(chars[i]); stringBuilder.append(chars[i]); } } System.out.println(stringBuilder.toString()); }
}