科大讯飞笔试，难受一批。。。%0

public class Main {

public static void main(String[] args) {

String str=null;
String string="";

Scanner scanner=new Scanner(System.in);
while (scanner.hasNext()) {
str=scanner.next();
for (int i = 0; i < str.length(); i++) {

if ((int)str.charAt(i)>=48&&(int)str.charAt(i)<=57) {
string+=str.charAt(i);

}
}
char arr[]=new char[string.length()];
for (int i = 0; i < arr.length; i++) {
arr[i]=string.charAt(i);

}
Arrays.sort(arr);

for (int i = 0; i < arr.length; i++) {

System.out.print(arr[i]);
}
}
scanner.close();
}
}