using System;
using System.Collections.Generic;
using System.Linq;

    class Program
    {
        static void Main(string[] args)
        {
           var list = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToList();
           list.Sort();
           list.RemoveAt(0);
           list.RemoveAt(list.Count()-1);
           Console.WriteLine("{0:f2}",list.Average());
        }
    }