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#include <cmath>
using namespace std;
const double pi = acos(-1.0), eps = 1e-6;
int main()
{
double w, h, s, d;
while (scanf("%lf %lf", &w, &h) == 2)
{
if (fabs(w) < eps && fabs(h) < eps)
break;
if (h < w)
swap(w, h);
d = h / (pi + 1);
d = min(d, w);
s = pi * d * d * 0.25 * w;
d = 2.0 * h / 3.0;
if (pi * d <= w)
{
d = min(d, w);
s = max(s, pi * h * h * h / 27.0);
}
s = max(s, w * w * (pi * h - w) / (4 * pi * pi));
printf("%.3lf\n", s);
}
return 0;
}
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