cezar

# -*- coding: utf-8 -*-
from io import open

__author__ = 'entsmv'


def obr(x):
    for i in range(1000):
        if (x * i) % m == 1:
            return i


def euclid(x, y):
    while x != y:
        if x > y:
            x -= y
        else:
            y -= x
    return True if x == 1 else False


alph = u'абвгдеёжзийклмнопрстуфхцчшщъыьэюя'
#alph = u'abcdefghijklmnopqrstuvwxyz '
m = len(alph)
alph2 = [u'' for i in range(m)]

k, n = 4, 7
if not euclid(m, n):
    print('ERROR')
    exit()

for i in range(m):
    alph2[i] = alph[(i * n + k) % m]

file = open('input.txt', encoding='utf-8')
out_file = open('output.txt', 'w', encoding='utf-8')

for line in file:
    for i in line:
        try:
            ind = alph.index(i)
        except:
            continue
        out_file.write(alph2[ind])
    out_file.write('\n'.decode('utf-8'))

out_file.close()
out_file = open('output.txt', encoding='utf-8')
out_file2 = open('output2.txt', 'w', encoding='utf-8')
for line in out_file:
    for i in line:
        try:
            ind = alph2.index(i)
        except:
            continue
        r = (((ind - k + m) % m) * obr(n)) % m
        out_file2.write(alph2[r])
    out_file2.write('\n'.decode('utf-8'))