#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)
#include <utility>		//swap, pair
#include <deque>		//deque
#include <climits>		//INT_MAX
#include <bitset>		//bitset
#include <cmath>		//sqrt, ceil. M_PI, pow, sin
#include <ios>			//fixed
#include <iomanip>		//setprecision
#include <sstream>		//stringstream

using namespace std;

int main() {

	vector<int> S(6);
	for (int i = 0; i < 6; i++) {
		cin >> S[i];
	}

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

	double sum = 0;
	for (int i = 1; i < 5; i++) {
		sum += S[i];
	}

	double ans = sum / 4.0;

	cout << fixed << setprecision(2) << ans << endl;

	return 0;

}