Sort String: Letters Followed by Digits

You are given a string s consisting of lowercase English letters and digits. The task is to rearrange the characters in the string such that all letters appear first in alphabetical order, followed by all digits in ascending order.

More formally, let \( \mathcal{L} \) be the sequence of letters extracted from s and \( \mathcal{D} \) be the sequence of digits from s. Your goal is to output the concatenation of \( sort(\mathcal{L}) \) and \( sort(\mathcal{D}) \), where the letters are sorted according to the standard lexicographical order and the digits are sorted numerically.

Input Format: A single string that contains lowercase alphabets and digits.

Output Format: A single string after sorting letters and digits as described.

inputFormat

The input consists of a single line containing a non-empty string s of lowercase letters and digits. There are no spaces in the input.

outputFormat

Output a single string that starts with all letters of s sorted in alphabetical order, followed by all digits of s sorted in increasing order.

b3a1c2

abc123