import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next(), tmp;
		String[] str = { "9", "8", "7", "6", "5", "4", "3", "2", "1", "0" };
		int n;
		for (int i = 0; i < 10; i++) {
			tmp = s.replaceAll(str[i], "");
			n = s.length() - tmp.length();
			for (int j = 0; j < n; j++) {
				System.out.print(str[i]);
			}
		}
		System.out.println();
	}
}