#include<iostream>
#include<iomanip>
#include<fstream>

using namespace std;

int main()
{
    ifstream input("competition.in");
    ofstream output("competition.out");

    double p1,p2,p3;

    double answer;

    input >> p1 >> p2 >> p3;

    answer = p1*0.05 + p2*0.1 + p3*0.15;
    if(answer>=6.00) answer = 6.00;
    else if(answer<=2.99) answer = 2.00;

    output << fixed << setprecision(2) << answer << endl;
}