(The original statement in Catalan has some jokes. This English version goes straight to the point of the problem.)
A palindrome has been broken into pieces. Put the pieces together in the right order.
Input
Input consists of several cases. Every case begins with the number of pieces n. Follow the n pieces, made up of only lowercase letters. Assume 1 ≤ n ≤ 8.
Output
For every case, print the palindrome that can be made by joining all the pieces. There is always exactly one solution.
Input
8 da ba learro zal azo rra ela bad 3 b a a 2 votemos someto 1 pop
Output
dabalearrozalazorraelabad aba sometovotemos pop