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

#define rep(i, n) for (int i = 0; i < (int)n; i++)

int main() {
  int a, b, c;
  cin >> a >> b >> c;
  double s = (a + b + c) / 2;
  double ss = sqrt(s * (s-a) * (s-b) * (s-c));
  double r = ss * 2 / (a + b + c);
  cout << fixed << setprecision(10) << r << endl;
  return 0;
}