#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <cmath>
#include <string>
#include <sstream>
#include<sstream>
#include <queue>
#include <limits>
#include <cstdlib>
#include <deque>
#include <map>
#include <set>
#include <iomanip>
using namespace std;



int main() {

	vector<double> points;

	double point =0.00;

	for(int i=0; i<6; i++){
		cin>>point;

		points.push_back(point);
	}

	sort(points.begin(),points.end());

	cout<<fixed<<setprecision(2)<<(points[1]+points[2]+points[3]+points[4])/4.00<<endl;



	return 0;
}