Sort Digits

Given a string S containing only digits (0-9), your task is to output a new string in which the digits are sorted in ascending order. If the input string is empty, you should output an empty string.

For example, if S = "3141592653", the correct output is "1123345569".

The challenge is to correctly sort the digits and handle potential edge cases.

inputFormat

A single line containing a string S consisting only of digits (0-9). Input is provided via standard input (stdin).

outputFormat

A single line containing the sorted string of digits, printed to standard output (stdout).## sample

3141592653

1123345569