Problem Statement

You are given a string S. Find the lexicographically smallest string S' obtained by permuting the characters of S.
Here, for different two strings $s = s_1 s_2 \ldots s_n$ and $t = t_1 t_2 \ldots t_m, s \lt t$ holds lexicographically when one of the conditions below is satisfied.

• There is an integer i\ $(1 \leq i \leq \min(n,m))$ such that $s_i \lt t_i$ and s_j=t_j for all integers j\ $(1 \leq j \lt i)$.
• s_i = t_i for all integers i\ $(1 \leq i \leq \min(n,m))$, and $n \lt m$.

Input

Input is given from Standard Input in the following format:
S

Output

Print the lexicographically smallest string S' obtained by permuting the characters in S.

Constraints

• S is a string of length between 1 and $2 \times 10^5$ (inclusive) consisting of lowercase English letters.

Sample Input 1

aba

Sample Output 1

aab

Three strings can be obtained by permuting aba:

• aba
• aab
• baa

The lexicographically smallest among them is aab.

Sample Input 2

zzzz

Sample Output 2

zzzz

见题面 Input 部分

见题面 Output 部分