Sort String: Letters Before Digits

You are given a string S which contains both alphabetical characters (letters) and digits. Your task is to rearrange the characters in S such that:

• All the letters appear in ascending order.
• Followed by all the digits in ascending order.

For example, if S = "d3b2a1c4", the output should be "abcd1234" because the letters sorted are a, b, c, d and the digits sorted are 1, 2, 3, 4.

Note: The execution format is via standard input (stdin) and standard output (stdout).

inputFormat

The input consists of a single line containing the string S which includes both letters and digits.

You may assume that S has length at most 10⁵ and contains only alphanumeric characters.

outputFormat

Output a single line --- the rearranged string where all letters (in ascending order) come first and all digits (in ascending order) come next.

d3b2a1c4

abcd1234