CSES - Palindrome Reorder
  • Time limit: 1.00 s
  • Memory limit: 512 MB
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
  • $1 \le n \le 10^6$
Example

Input:
AAAACACBA

Output:
AACABACAA