The topic of this problem is cryptography. Each of the input files contains a cipher. Decrypting it will probably involve more steps. After successfully completing all of them you will get the final answer: a word or a short phrase. To solve the corresponding test case, submit an output file with one line of the form:
SOLUTION: (the final answer)
Note that you may make 10 submits for each of the input files. If you get stuck and don't have a clue what to do next, you may sacrifice one submit to get an automatic hint from us.
Getting a hint will be a gamble, as we don't know what your progress is and what kind of a hint do you need. Still, we tried to be helpful – we labeled the hints and ordered them so that their order now approximately corresponds to the intended progress in solving the problem. If you want a hint, you may try to estimate your progress and ask for a hint that you think will help you the most.
If you want to ask for a hint, submit an output file with one line of the form:
HINT: (the label of the hint)
The tester will reply with the corresponding hint. Note that if you ask for the same hint for the second time, you won't get anything new ;) Also note that you have to use the correct DIS when submitting – H1 for submissions concerning the easy input, H2 for submissions concerning the hard input.
Hint labels for the easy input:
Credits:
Problemsetter(s): Yulka, misof
Contest-related materials: Yulka, misof