#提取不重复的整数 java-LinkedHashMap#

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);
        HashMap<Character, Integer> map = new LinkedHashMap<>();
        char[] chars = string.toCharArray();
        for (int i = chars.length - 1; i > -1 ; i--) {
            map.put(chars[i], 0);
        }

        Set<Map.Entry<Character, Integer>> entries = map.entrySet();
        for (Map.Entry<Character, Integer> entry : entries) {
            System.out.print(entry.getKey());
        }
    }


}