import java.util.Arrays;
import java.util.Scanner;

public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()){
			double[] s=new double[6];
			double sum=0;
			for(int i=0;i<6;i++){
				s[i]=sc.nextDouble();
				sum+=s[i];
			}
			Arrays.sort(s);
			System.out.printf("%.2f\n",(sum-s[0]-s[5])/4);
		}
	}
}