#提取不重复的整数 java-LinkedHashSet#

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
//        HJ9 统计不重复整数
        Scanner scanner = new Scanner(System.in);
        int number = scanner.nextInt();
        String string = Integer.toString(number);
        HashSet<Character> set = new LinkedHashSet<>();
        char[] chars = string.toCharArray();
        for (int i = chars.length - 1; i > -1 ; i--) {
            set.add(chars[i]);
        }
        for (Character character : set) {
            System.out.print(character);
        }
    }


}