import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String[] inputs = reader.readLine().split(" ");
        int max = Integer.MIN_VALUE;
        int min = Integer.MAX_VALUE;
        int sum = 0;
        for (int i = 0; i < 6; i++) {
            int point = Integer.parseInt(inputs[i]);
            max = Math.max(max, point);
            min = Math.min(min, point);
            sum += point;
        }
        sum = sum - min - max;
        System.out.printf("%.2f",sum/(4.0));
    }
}