#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>

using namespace std;


int main() {

    vector<double> ss;
    for (int i = 0; i < 6; ++i) {
        double S;
        cin>>S;
        ss.push_back(S);
    }
    sort(ss.begin(),ss.end());
    double result =0;
    for (int i = 1; i < 5; ++i) {
        result += ss[i];
    }

    result  = result / 4.00;

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

    return 0;
}