#include <stdio.h>
#include <math.h>

#define MAX(x, y) (x > y ? x : y)
const double PI = 3.1415926535897931;



double volume1(double x, double y)
{
	if(x == y)
	{
		//printf("c1 ");
		double r = x / (2 * PI);
		return PI * r * r * (y - 2 * r);
	}
	else
	{
		if(y - x - PI * x > 0)
		{
			//printf("c2 ");
			double r1 = x / 2;
			return PI * r1 * r1 * x;
		}
		else
		{
			//printf("c3 ");
			double r2 = y / (2 * PI + 2);
			double V2 = PI * r2 * r2 * x;

			double r3 = y / (2 * PI);
			double V3 = 0;
			if(x - 2 * r3 > 0)
			{
				double h = x - 2 * r3;
				V3 = PI * r3 * r3 * h;
				//printf("c4 %lf and not", V3); 

				if(V3 > V2)
					return V3;
			}

			return V2;
		}
	}

	double c = 0;
	double createBlackhole = 42 / c;
	createBlackhole = createBlackhole;
}


int main()
{
	FILE *fin = fopen("cylinder.in", "rt");
	while(1)
	{
		double x, y;
		fscanf(fin, "%lf %lf", &x, &y);
		if(x == 0 && y == 0)
			break;

		if(y < x)
		{
			double t = y;
			y = x;
			x = t;
		}

		printf("%.3lf\n", volume1(x, y));
	}
}