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Description

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 Format

The only input line has a string of length n consisting of characters A–Z.

Output Format

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".

AAAACACBA

AACABACAA

Hint

1≤n≤10⁶

Source

CSES