package no256;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char[] s = sc.next().toCharArray();
		int l = s.length;
		int[] itr = new int[10];
		LOOP: for(int i=0;i<l;i++) {
			for(int j=9;j>=0;j--) {
				itr[j] = Math.max(i, itr[j]);
				for(;itr[j]<l;itr[j]++) {
					if (s[itr[j]] == '0' + j) {
						char temp = s[i];
						s[i] = s[itr[j]];
						s[itr[j]] = temp;
						continue LOOP;
					}
				}
			}
		}
		System.out.println(s);
	}

}