#include<stdio.h>
#include<math.h>
int main()
{
    double r,s,a,b,c,d,e,f,g,h;
    while(scanf("%lf%lf%lf",&a,&b,&c)!=EOF)
    {
        if(a==0 || b==0 || c==0)
        {
            printf("The radius of the round table is: 0.000\n");
        }
        else
        {
            s=(a+b+c)/2;
            d=s-a;
            e=s-b;
            f=s-c;
            g=s*d*e*f;
            h=sqrt(g);
            r=h/s;
            printf("The radius of the round table is: %.3lf\n",r);
        }
    }
    return 0;
}