#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    double A, B, C;
    cin >> A >> B >> C;
    
    double s = (A + B + C) / 2;
    double S = sqrt(s*(s - A)*(s - B)*(s - C));
    
    cout << fixed << setprecision(15) << 2*S / (A + B + C) << '\n';
}