#include <bits/stdc++.h>

using namespace std;

int main()
{
    double sum = 0, crt;
    double mn = 100, mx = 0;
    for (int i = 0; i < 6; i++) {
        scanf("%lf", &crt);
        mn = min(mn, crt);
        mx = max(mx, crt);
        sum += crt;
    }
    printf("%.2f\n", (sum - mx - mn) / 4);
}