using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        string cnt = Console.ReadLine();
        string str = Console.ReadLine();
        string[] before = str.Split(' ');
        int[] after = before.Select(s => int.Parse(s)).ToArray();
        int center = 0;
        double output = 0;

        Array.Sort(after);

        if (after.Length % 2 != 0)
        {
            center = after.Length / 2;
            output = after[center];
        }
        else
        {
            center = after.Length / 2 - 1;
            output = (after[center] + after[center + 1]) / 2.0;
        }


        Console.WriteLine(output);
        Console.ReadLine();
    }
}