using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp19
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] numArray = Console.ReadLine().Split(' ');
            double[] array = new double[numArray.Length];
            double result = 0;

            for (int i = 0; i < numArray.Length; i++)
            {
                array[i] = double.Parse(numArray[i]);
            }

            Array.Sort(array);

            if (n % 2 != 0)
            {
                result = array[n/2];

            }
            else if (n % 2 == 0)
            {
                double a = array[n / 2];
                double b = array[(n / 2)- 1];
                result = (a + b) / 2;
            }


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