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

namespace yukicoder_275{
    class Program{
        static void Main(string[] args){
            int n = int.Parse(Console.ReadLine());
            string[] s = Console.ReadLine().Split(' ');
            int[] a = new int[n];
            for(int i = 0; i < n; i++) {
                a[i] = int.Parse(s[i]);
            }
            Array.Sort(a);
            if (n % 2 == 1) {
                Console.WriteLine(a[(n - 1) / 2]);
            }else {
                double num = ((double)a[n / 2 - 1] + (double)a[n / 2]) / 2; 
                Console.WriteLine(num);
            }
            Console.ReadLine();
        }
    }
}