题解 | #图片整理#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        int[] a = new int[128];
        for (int i = 0; i < s.length(); i++) {
            int k = s.charAt(i);
            a[k]++;
        }
        for (int j = 48; j < 128; j++) {
            if (a[j] != 0) {
                for (int x = 0; x < a[j]; x++) {
                    System.out.print((char)j);
                }
            }
        }
        System.out.println();
    }
}