\includegraphics{https://static.e-olymp.com/content/40/4078ce58c019ee57719e97e1c617d02a5fd96519.jpg} On a leaflet in a section with a cell in \textbf{M} millimeters have drawn a circle in radius of \textbf{R} millimeters and have painted over all the cells crossed with a circle. All other cells including what circles only concern, have left not painted over. The center of a circle is always placed on crossing of cells. To define, how many cells \textbf{N} have been painted over. \InputFile In a unique line through a blank of \textbf{2} numbers: \textbf{M} and \textbf{R} (\textbf{M}, \textbf{R} <= \textbf{40000}). \textbf{Output} Required number of painted over cells \textbf{N} .