#include<iostream>
#include<iomanip>

using namespace std;

int main(){
    double p,q,r;
    cin >> p >> q >> r;
    if((p == 0 && q == 0) || (q == 0 && r == 0) || (p == 0 && r == 0)){
        double p = max(p/(p+q+r),q/(p+q+r));
        p = max(p,r/(p+q+r));
        cout << fixed << setprecision(10) << p << endl;
        return 0;
    }
    double ans = max((2*p+2*q+2*r)/(3*p+6*r),(2*p+2*q+2*r)/(3*p+6*q));
    ans = max(ans,(2*p+2*q+2*r)/(3*q+6*r));
    cout << fixed << setprecision(10) << ans << endl;
    return 0;
}