\problemname{DRM Messages}
DRM Encryption is a new kind of encryption.  Given an encrypted string (which
we'll call a {\em DRM message}), the decryption process involves three steps:
Divide, Rotate and Merge.  This process is described in the following example
with the DRM message ``EWPGAJRB'':

\begin{description}
\item[Divide] -- First, divide the message in half to ``EWPG'' and ``AJRB''.
\item[Rotate] -- For each half, calculate its rotation value by summing up the
%values of each character (A = 0, B = 1, ... Z = 25). The rotation value of
%``EWPG'' is 4 + 22 + 15 + 6 = 47. Rotate each character in ``EWPG'' 47 positions
values of each character ($\textrm{A} = 0, \textrm{B} = 1, \ldots, \textrm{Z} = 25$). The rotation value of
``EWPG'' is $4 + 22 + 15 + 6 = 47$. Rotate each character in ``EWPG'' $47$ positions
forward (wrapping from Z to A when necessary) to obtain the new string ``ZRKB''.
Following the same process on ``AJRB'' results in ``BKSC''.
\item[Merge] -- The last step is to combine these new strings (``ZRKB'' and
``BKSC'') by rotating each character in the first string by the value of the
corresponding character in the second string. For the first position, rotating
`Z' by `B' means moving it forward 1 character, which wraps it around to `A'.
Continuing this process for every character results in the final decrypted
message, ``ABCD''.
\end{description}

\section*{Input}
The input contains a single DRM message to be decrypted. All characters in the
string are uppercase letters and the string's length is even and $\leq 15\,000$.

\section*{Output}
Display the decrypted DRM message.
