Ladder is a set of cubes in which each over the top layer contains fewer blocks than the previous one. \includegraphics{https://static.e-olymp.com/content/e7/e791b82e44d503359cb142b1a6f0a9223e7be403.jpg} Count the number of ladders that can be built from \textbf{n }blocks. \InputFile One integer \textbf{n }(\textbf{1 }≤ \textbf{n }≤ \textbf{100}). \OutputFile Print the required number of ladders.