using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {
            double i, k = 0 , sum = 0;
            int N = int.Parse(Console.ReadLine());

            var s = Console.ReadLine();
            var z = s.Split(" ");
            double[] ints = new double[z.Length];
            for (i = 0; i <= z.Length - 1; i++)
            {
                ints[(int)k] = double.Parse(z[(int)i]);
                sum += ints[(int)k];
                k++;
            }
            Array.Sort(ints);
            double ty = ints.Length % 2;
            if ( ty == 1)
            {
                Console.WriteLine(ints[ints.Length / 2]);
            }
            else if (ty == 0)
            {
                double aa = ints[ints.Length / 2 - 1] ;
                double bb = ints[ints.Length / 2 ];
                double cc = (aa + bb) / 2;
                Console.WriteLine(cc);
            }
        }
    }
}