Given a string, your task is to reorder its letters in such a way that it becomes a palindrome (i.e., it reads the same forwards and backwards).

Input

• The only input line has a string of length \(n\) consisting of characters A-Z.

Output

• Print a palindrome consisting of the characters of the original string. You may print any valid solution. If there are no solutions, print NO SOLUTION.

Constraints

• \(1 \leq n \leq 10^6\)

Example

Sample input

AAAACACBA

Sample output

AACABACAA