The painted over sections 2#296
On a sheet with a grid of cells of size millimeters, a circle with radius millimeters is drawn. All cells that intersect with the circle are painted. All other cells, including those that only touch the circle, are left unpainted. The center of the circle is always placed at the intersection of grid lines. Determine the number of painted cells.
A single line contains two integers and (M, R \leq 40000), separated by a space.
Output the number of painted cells.
Example 1