#842. Letters only in the first word
You get two words. Print the different letters that are in the first word but not in the second, in alphabetical order. If there are none, print `None`.
### Input
Two lines.
### Output
One line.
Examples
Input
code loop
Output
cde
Input
refer banana
Output
efr
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.