#include <bits/stdc++.h>
using namespace std;

int main()
{
	double a, b, c;
	cin >> a >> b >> c;
	double p = (a + b + c) / 2;
	double s = sqrt(p * (p - a) * (p - b) * (p - c));
	
	double r = 2 * s / (a + b + c);
	cout << fixed << setprecision(10) << r << endl;
}