# Problem D

Palindrome Substring

A palindrome is a word or phrase that reads the same backwards or forwards. For this problem, we’re going to find all the different palindromes that occur inside a string.

We’ll say that string $a$ is a *nontrivial
palindrome substring* of $b$ if $a$ is a substring of $b$, the sequence of characters in
$a$ reads the same
forwards or backwards, and $a$ is at least two characters long.
Here, a substring of $b = b_1 b_2
\ldots b_ n$ is any string $b_ i b_{i+1} \ldots b_{i+j}$ where
$i \geq 1$ and
$j \geq 1$ and
$i + j \leq n$.

## Input

Input consists of up to $100$ lines. Each line contains a string of $1$ to $1000$ characters chosen from a–z. Input ends at end of file.

## Output

For each input string, print out the list of all of its non-trivial palindrome substrings. Each list of palindromes should be sorted lexicographically, and should not contain duplicates. Print a blank line after the output for each input string.

Sample Input 1 | Sample Output 1 |
---|---|

thisisatest xxxxoooo |
isi sis oo ooo oooo xx xxx xxxx |