\includegraphics{https://static.e-olymp.com/content/0d/0deb12c1ef6f1c7b9a78066b1ba28b80488fdfaa.gif} In this task, Vasilyek, acting as an adult child who no longer believed that St. Nicholas carries gifts. But every year, waking up on \textbf{December 19}, sunet hand under the pillow. In that year he decided to ask the parents, so they gave him a brand new laptop. In response to his request, his father said: "If you decide to challenge that you are already a few days you can not overpower, you will have happiness". The task was as follows. Given a rectangle of \textbf{N}*\textbf{M}, divided by the unit square. In one operation to carry out all possible diagonals in all the squares, which were before the operation. This operation must be repeated K times. You must then count the number of triangles in the middle of which nebylo held a single segment. Remain covsem little, so Vasilyek need your help. \InputFile In the first row are given two natural numbers \textbf{N} and \textbf{M} - the size of the rectangle. Second line is given an integer \textbf{K} - the number of applications of the operation. \OutputFile The answer to this Vasilyek task. It is guaranteed that the answer will not exceed \textbf{10^18}.