task_1_2_3.py

# coding=utf-8
ALPHABET = u'абвгдеёжзийклмнопрстуфхцчшщъыьэюя'

with open('text.txt') as f:
    lines = f.readlines()
    lines = [line.decode("utf-8") for line in lines]


print '###TASK 1:'
for line in lines:
    if len(line) > 20:
        print line


print '###TASK 2'

text_no_lines = ''.join(lines)

CODES = []
for letter in ALPHABET:
    CODES.append(text_no_lines.rfind(letter))

for code, letter in zip(CODES, ALPHABET):
    print code, letter


print '###TASK 3'

words = []
strr = raw_input('Enter word to encrypt: ').decode("utf-8")

while strr:
    words.append(strr)
    strr = raw_input('Enter word to encrypt: ').decode("utf-8")

e_words = []
for word in words:
    e_word = ''
    for letter in word:
        index = ALPHABET.find(letter)
        c = CODES[index]
        e_word += str(c)
    e_words.append(e_word)

print ' '.join(e_words)