Given rectangle \textbf{m} × \textbf{n}. To count the number of ways to split it into two parts, each of which is a connected set of unit cells. For example, there are six ways to break this way a square \textbf{2} × \textbf{2}, they are shown in the following figure. \includegraphics{https://static.e-olymp.com/content/a8/a801ee80e3dd23ff8bf6b4f34a24edb1c86cb7c6.jpg} \InputFile The input file contains two integers \textbf{m} and \textbf{n} (\textbf{1} ≤ \textbf{m}, \textbf{n} ≤ \textbf{11}). \OutputFile Derive the output file a single number - the required number of ways.