Odd One Out

Given a sequence of uppercase words of equal length. For each word, compute the sequence of signed differences between adjacent letters; return the word whose difference sequence differs from all the others. Exactly n−1 words are guaranteed to share the same difference sequence, and the remaining one is different.

This site uses a standard input/output protocol.

输入格式

The first line contains n, followed by n lines of words. 3≤n≤26, 2≤word length≤26; the words in a test all have the same length and contain only uppercase English letters.

输出格式

Output the one word that is different.

样例 1

输入：

4
ACB
BDC
CED
DEF

输出：

DEF

样例 2

输入：

4
ABC
BCD
CDE
CBA

输出：

CBA

样例 3

输入：

3
AA
BC
DE

输出：

AA