# Problem F

Suffidromes

Given two strings of lowercase letters, $a$ and $b$, print the shortest string $x$ of lowercase letters such that exactly one (but not both) of $ax$ or $bx$ is a palindrome; that is, equal to itself when reversed.

## Input

Standard input contains several pairs of $a$ and $b$ (at most $500$). Each string is on a separate line and consists of between $0$ and $1\, 000$ lowercase letters.

## Output

For each pair, output a line containing $x$. If several $x$ satisfy the criteria above, choose
the first one in alphabetical order. If no such string
$x$ exists, print
“`No solution.`” as answer.

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

abab ababab abc def |
baba ba |