# Cipher
# name: DM
# Date: 1-19-2017

import string

#define alphabets
l_case = string.ascii_lowercase
u_case = string.ascii_uppercase
alphabet = l_case + u_case

print ("************* Optional Exercise: Cipher ***********")

# Request user input for encoded phrase & shift value
phrase = str(input("Please enter a phrase to encode: "))
shift_value = int(input("Please enter a shift value: "))

# Set up empty string in which to put results of encryption
encoded_phrase = ""

#  Ascii for reference:
#
#      A = 65         a = 97
#      Z = 90         z = 122

for c in phrase:
    #set up similar cases for both upper & lower case alphabets, making sure to change back the type from ord to chr
    if c in l_case:
        o = ord(c)
        # in cases where the shift would 'run over' the end of the ascii l_case alphabet, which terminates at z = 122, need to use the distance between the 'end of the line' (122) and the character to be encrypted.
        if o + shift_value > 122:
            # use d = 123 - o instead of d = 122 - o to be inclusive of 122
            d = 123 - o
            o = 97 + d
            encoded_phrase += chr(o)

        else:
            encoded_phrase += chr(o + shift_value)
    if c in u_case:
        y = ord(c)
        if y + shift_value > 90:
            d = 91 - y
            y = 65 + d
            encoded_phrase += chr(y)
        else:
            encoded_phrase += chr(y + shift_value)
    elif c not in alphabet:
        encoded_phrase += c

print (encoded_phrase)