#Description:
#Everyone knows passphrases. One can choose passphrases from poems, songs, movies names and so on but frequently they can be #guessed due to common cultural references. You can get your passphrases stronger by different means. One is the following:
#choose a text in capital letters including or not digits and non alphabetic characters,
#shift each letter by a given number but the transformed letter must be a letter (circular shift),
#replace each digit by its complement to 9,
#keep such as non alphabetic and non digit characters,
#downcase each letter in odd position, upcase each letter in even position (the first character is in position 0),
#reverse the whole result.
#Example:
#your text: "BORN IN 2015!", shift 1
#1 + 2 + 3 -> "CPSO JO 7984!"
#4 "CpSo jO 7984!"
#5 "!4897 Oj oSpC"
#With longer passphrases it's better to have a small and easy program. Would you write it?
#https://en.wikipedia.org/wiki/Passphrase

def play_pass(s, n):
    x = 'abcdefghijklmnopqrstuvwxyz'
    index_ = 0
    total = ''
    for i in range(len(s)):
        if s[i].isalpha():
            index_ = x.index(s[i].lower()) + n
            while index_ > 25 or index_ < 0:
                index_ = abs(26 - abs(index_))
            if i % 2 == 0:
                total += x[index_].upper()

            else:
                total += x[index_].lower()

        elif s[i].isdigit():
            index_ = abs(9 - int(s[i]))
            total += str(index_)
        else:
            total += s[i]
    return total[::-1]