import java.util.*; public class Main{ public static void main(String[] args){ Scanner sc=new Scanner(System.in); while(sc.hasNext()){ int in=sc.nextInt(); LinkedHashSet<Character> set=new LinkedHashSet<Character>(); String s=String.valueOf(in); for(int i=s.length()-1;i>=0;i--){ char target=s.charAt(i); set.add(target); } set.forEach(x->System.out.print(x)); } System.out.println(); } }