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

namespace lecture
{
    class Program
    {

        static void Main(string[] args)
        {
            int a = 0;
            double result = 0;

            int n = int.Parse(Console.ReadLine());
            double[] data = Console.ReadLine().Trim().Split(' ').Select(x => double.Parse(x)).ToArray();
            Array.Sort(data);
            // 真ん中の計算
            a = n / 2;
            // 中央値の計算
            if (data.Length % 2 == 0)
            {
                result = (data[a-1] + data[a]) / 2;
            }
            else
            {
                result = data[a];
            }
            Console.WriteLine(result);
        }
    }
}