using System;

namespace ConsoleApp11
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine().Split(' ');

            double[] S = new double[6];

            double tem;

            double sum = 0;

            double average = 0;

            for(int i = 0; i < 6; i++)
            {
                S[i] = double.Parse(input[i]);
            }

            for(int i = 0; i < 5; i++)
            {
                for(int j = i + 1; j < 6; j++)
                {
                    if(S[i] > S[j])
                    {
                        tem = S[j];
                        S[j] = S[i];
                        S[i] = tem;
                    }
                }
            }

            for(int i = 1; i < 5; i++)
            {
                sum += S[i];
            }

            average = sum / 4.0;
            average = average * 100.0;

            Console.WriteLine(Math.Truncate(average) / 100.0);

        }
    }
}