The program executes a character encryption of the input stream and sends results to the output stream.
Scheme of the program:

The encryption algorithm is unknown – it is re-generated for each copy of the program (when generated,
it is checked by correctness).

The task is to understand the encryption algorithm, write decoder and send its text in C as a solution
(Clang 3.8 is used).


Stream encryption

The character stream on the input and the encrypted stream on the output. Decryptor required.

Music and words are folk,