#include<iostream>
#include<cmath>
#include<fstream>
using namespace std;
double a,b,c;
double result;
int main()
{
    freopen("competition.in","r",stdin);
    freopen("competition.out","w",stdout);
    cin>>a>>b>>c;
    result=((a*5)/100)+b/10+((c*15)/100);
    if(result<3){
        cout<<"2.00\n";
        }else{
    if(result>6)
        cout<<"6.00\n";
        else
            cout<<floor(result)<<"."<<(result-floor(result))*100<<endl;
            //cout<<result<<endl;
        }

}