Alex is at the origin. But he wants to get to the shore of the lake, which is by some reason at the point (\textbf{x}, \textbf{y}). Probably, because tree grows there. At the shop nearby he bought speedwalking boots, with help of which he can step exactly by \textbf{d} distance. Determine, what minimal number of steps is required to get to the destination. Point (\textbf{x}, \textbf{y}) doesn't match with origin. Alex can step to any point of our flat world. \InputFile One line contains three integers \textbf{x}, \textbf{y}, \textbf{d }(-\textbf{10000} ≤ \textbf{x}, \textbf{y} ≤ \textbf{10000}, \textbf{1} ≤ \textbf{d} ≤ \textbf{10000}). \OutputFile Print the minimal number of steps.