#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)

int main() {
    int s, sMax = INT_MIN, sMin = INT_MAX, tot = 0;
    REP(i, 6) {
        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;
}