Final-Challenge.md

Problem Statement

You will create a program that will find the missing letter from a string and return it. If there is no missing letter, the program should return "none".

Input format

Input must contain the string S (2<S<=100)

Output format

Display only the missing letter

Example 1

Input

        ghiklm

Output

        j

Example 2

Input

        abcde

Output

        none

Example 3

Input

        abdf

Output

        c e