Baekjoon1427

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

public class baekjoon1427{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int number = scan.nextInt();
        scan.close();
        ArrayList<Integer> arr = new ArrayList<>();
        do{
            int remain = number % 10;
            number /= 10;
            arr.add(remain);
        }while(number>0);
        Collections.sort(arr,Comparator.reverseOrder());
        for(int x : arr) System.out.print(x);
    }
}