#include <cstdio>
#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;
const double sp=0.99,eps=1e-8;
double a,b,c,d,e,f,M=1e9;
double dirx[]={-1,-1,-1,0,0,1,1,1};
double diry[]={-1,0,1,-1,1,-1,0,1};

double dis(double x,double y,double z)
{
    return sqrt(x*x+y*y+z*z);
}

double getz(double x,double y)
{
    double A=0,B=0,C=0;
    A=c;
    B=d*y+e*x;
    C=a*x*x+b*y*y+f*x*y-1;
    double delta=B*B-4*A*C;
    if(delta<0) return M;
    double z1=(sqrt(delta)-B)/(2.0*A),z2=(-sqrt(delta)-B)/(2.0*A);
    if(z1*z1<z2*z2) return z1;
    return z2;
}

double solve()
{
    double x=0,y=0,z=0,tx=0,ty=0,tz=0,step=1;
    z=getz(x,y);
    while(step>eps)
    {
        for(int i=0;i<8;i++)
        {
            tx=x+dirx[i]*step;
            ty=y+diry[i]*step;
            tz=getz(tx,ty);
            if(tz>=M) continue;
            if(dis(tx,ty,tz)<dis(x,y,z))
            {
                x=tx,y=ty,z=tz;
            }
        }
        step*=sp;
    }
    return dis(x,y,z);
}

int main()
{
    while(scanf("%lf%lf%lf%lf%lf%lf",&a,&b,&c,&d,&e,&f)!=EOF)
    {
        printf("%.8lf\n",solve());
    }
    return 0;
}