import java.util.Scanner;
import java.text.DecimalFormat;

public class Study01 {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String [] b = a.split(" ");
		int [] c = new int[6];
		int max = 0,min = 10000;
		for(int i=0;i<b.length;i++){
			c[i] = Integer.parseInt(b[i]);
			//System.out.println(c[i]);
			max = Math.max(max,c[i]);
			min = Math.min(min,c[i]);
		}
		DecimalFormat format = new DecimalFormat("#.#");
		format.setMinimumFractionDigits(2);
		format.setMaximumFractionDigits(2);
		double answer = 0;
		for(int i=0;i<6;i++){
			answer += c[i];
		}
		int hiki = max + min;
		answer = answer - hiki;
		answer /= 4;
		System.out.println(format.format(answer));
	}
}