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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            string[] input2 = Console.ReadLine().Split(' ');
            int[] num = new int[input2.Length];
            for(int i=0;i<num.Length;i++)
            {
                num[i] = int.Parse(input2[i]);
            }
            Array.Sort(num);
            if(num.Length%2==1)
            {
                Console.WriteLine(num[num.Length / 2]);
            }
            else
            {
                double ans = ((double)num[num.Length / 2] + (double)num[(num.Length / 2) - 1])/2;
                Console.WriteLine(ans);
            }
        }

    }
}