asdasdsadadas

#include <iostream>
#include <vector>
#include <cmath>
#include <iomanip>
#include <fstream>
using namespace std;

int main()
{

    ifstream f("case2_input.txt");
    if (f)
    {
        ofstream g("Output.txt");
        while (!f.eof())
        {
            double a, b, c;
            f >> a >> b >> c;

        if (b <= a && c <= a)
        {
            g << fixed << setprecision(5) << b * c << endl;
            continue;
        }
        else
        {
            double s = a * a, s1 = 1;
            if (b < a * sqrt(2))
            {
                double h = a * sqrt(2) / 2. - b / 2.;
                s -= 2 * (h * h);
            }
            if (a * sqrt(2) > c)
            {
                double h = a * sqrt(2) / 2. - c / 2.;
                s -= 2 * (h * h);
            }

            s1 = (max(b, c) - (max(b, c) - a)) * min(b, c);
            g << fixed <<  setprecision(5) << max(s, s1) << endl;
        }
        }


    }
    return 0;
}