/*Beavergnaw  棱台公式
2008-08-07 14:57:25 Accepted 1904 C++ 00:00.00 844K 天将降大任于我
棱台公式 ：(s1+s2+sqrt(s1*s2))*(1.0/3)*h      s1为上底,s2为下底,h为高
题中公式为(s1+s2+sqrt(s1*s2))* (1.0/3) *(D-d)/2+pi*(d/2)^2*d=pi(D/2)^2*D-v
化简为D^3-d^3=6v/pi
*/
#include<iostream>
#include<cmath>
using namespace std;
const double pi=3.1415926;
int main()
{
 int d1,v;double s;
 while(scanf("%d%d",&d1,&v)!=EOF)
 {
  if(d1==0&&v==0) break;
  else
  {
            s=d1*d1*d1-double(6*v)/pi;
   printf("%.3lf\n",pow(s,1.0/3));
  }
 }
 return 0;
}