Unique Palindromic Substrings

Given a string S, your task is to find all unique palindromic substrings of S and print them in lexicographical order. A palindrome is a string that reads the same backwards and forwards, i.e., it satisfies the condition $$S = S^R$$.

The solution should read the input string from standard input (stdin) and output the palindromic substrings separated by a single space to standard output (stdout).

inputFormat

The input consists of a single line containing the string S. The string will contain only lowercase letters.

outputFormat

Output a single line containing all unique palindromic substrings of S in lexicographical order, separated by a single space.

aab

a aa b