using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using static System.Console;
using static System.Math;

namespace CP
{
    class Atria
    {
        static void Main(string[] args)
        {
            int n = int.Parse(ReadLine());
            double[] s = ReadLine().Split(' ').Select(double.Parse).ToArray();
            Array.Sort(s);
            if (s.Length %2 != 0)
            {
                WriteLine(s[s.Length/2]);
            }
            else
            {
                WriteLine(
                    (s[s.Length/2] + s[(s.Length/2)-1])/2
                    );
            }
        }
    }
}