import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String N = scan.next();
		int []k = new int[10];
		Arrays.fill(k, 0);
		StringBuilder val = new StringBuilder();
		for(int i = 0; i < N.length(); i++) {
			char c = N.charAt(i);
			for(int j = 0; j < 10; j++) {
				if(j == Character.getNumericValue(c)) {
					k[j] ++;
				}
			}
		}
		scan.close();
		for(int i = 0; i < 10; i++) {
			if(k[9 - i] != 0) {
				String str = Integer.toString(9 - i);
				for(int j = 0; j < k[9 - i]; j++) {
					val.append(str);
				}
			}
		}
		System.out.println(val);
	}
}