# https://www.codewars.com/kata/58b8c94b7df3f116eb00005b
#
# # Task
#  Given a string `str`, reverse it omitting all non-alphabetic characters.
#
# # Example
#
#  For `str = "krishan"`, the output should be `"nahsirk"`.
#
#  For `str = "ultr53o?n"`, the output should be `"nortlu"`.
#
# # Input/Output
#
#
#  - `[input]` string `str`
#
#   A string consists of lowercase latin letters, digits and symbols.
#
#
#  - `[output]` a string


import string

def reverse_letter(s):
    alpha = string.ascii_lowercase
    return ''.join([letter for letter in s if letter in alpha][::-1])
