import java.util.Scanner;

/**
 * @author lushuifa
 * @version [版本号, 2022年04月01日}]
 * @ClassName : HJ9
 * @Description : 提取不重复的整数
 *
    输入:
    9876673
    复制
    输出:
    37689
 *
 * @since [2022-04-01]
 */
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String inputString = sc.nextLine();
            char[] chars = inputString.toCharArray();
            String output = "";
            for (int i = chars.length-1; i >= 0; i--) {
                if (output.indexOf(chars[i])==-1) {
                    output += chars[i];
                }
            }
            System.out.println(output);
        }
    }
}