uva 10297

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

int main()
{
    double pi=2*acos(0.00);
    double d,v,a_cylinder,a_conics,dif,ans;
    while(scanf("%lf%lf",&d,&v)==2)
    {
        if(d==0&&v==0)
            break;
        a_cylinder=pi*(pow(d/2.00,2))*d;
        a_conics=2*pi*(1.0/3.0)*(pow(d/2.00,3));
        dif=(a_cylinder-a_conics)-v;
        ans=cbrt((6.0*dif)/pi);

        printf("%.3lf\n",ans);
    }

}