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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
 
    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(20) << S/(a+b+c)*2 << endl;
}