#include <bits/stdc++.h>

using namespace std;

int main() {
    int sMax = -200;
    int sMin = 200;

    int tot = 0;
    for (int i = 0; i < 6; ++i) {
        int s;
        cin >> s;
        sMax = max(s, sMax);
        sMin = min(s, sMin);
        tot += s;
    }

    double ans = (tot - sMax - sMin) / 4.0;
    cout << fixed << setprecision(2);
    cout << ans << endl;
    return 0;
}