#include <iostream>

int main() {
    int sum = 0;
    int minN = 101;
    int maxN = -1;
    for(int i = 0; i < 6; i++) {
        int t; std::cin >> t;
        sum += t;
        minN = std::min(minN, t);
        maxN = std::max(maxN, t);
    }
    printf("%.2lf\n", (sum - minN - maxN) / 4.0);
}