#include <iostream>
using namespace std;
double mymax(double x,double y,double z)
{
    double s=x;
    if(y>s)
        s=y;
    if(z>s)
        s=z;
    return s;
}
int main()
{
    int a,b,c;
    cin >> a >> b >> c;
    printf("%.3f\n",mymax(a,b,c)/(mymax(a+b,b,c)*mymax(a,b,a+b)));
}