#include <atcoder/all>
#include <bits/stdc++.h>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    double a, b, c;
    cin >> a >> b >> c;
    double s = (a + b + c) / 2;
    double S = sqrt((double)s * (s - a) * (s - b) * (s - c));
    double r = S / s;
    cout.precision(12);
    cout << fixed;
    cout << r << endl;
}