import java.util.Scanner;
import java.util.stream.IntStream;

public class Main{

	static Scanner s=new Scanner(System.in);

	public static void main(String __[]){
		input();
		solve();
	}

	private static void input(){
	}

	private static void solve(){
		System.out.printf("%.2f\n",
				IntStream.of(
				s.nextInt(),
				s.nextInt(),
				s.nextInt(),
				s.nextInt(),
				s.nextInt(),
				s.nextInt())
				.sorted()
				.skip(1).limit(4).
				sum()

				/4.0);
	}
}