AT_abc426_b [ABC426B] The Odd One Out

You are given a string $ S $ of length at least $ 3 $ consisting of lowercase English letters. $ S $ contains exactly two types of characters, and exactly one character is different from the others. Find that one character. For example, if $ S $ is `odd`, report `o`.

The input is given from Standard Input in the following format: > $ S $

Print the answer.

### Sample Explanation 1 In `odd`, the character different from the others is `o`. ### Sample Explanation 2 In `dad`, the character different from the others is `a`. ### Sample Explanation 3 In `wwwwwwwwwv`, the character different from the others is `v`. ### Constraints - $ S $ is a string of length at least $ 3 $ and at most $ 10 $ consisting of lowercase English letters. - $ S $ contains exactly two types of characters, and exactly one character is different from the others.