using System;

public class Program{
    public static void Main(){
        string s = Console.ReadLine();
        string[] input = Console.ReadLine().Split(' ');
        double[] array = new double[input.Length];
        double answer = 0;
        
        for(int i = 0; i < input.Length; i++)
        {
            array[i] = double.Parse(input[i]);
        }
        
        Array.Sort(array);
        
        //偶数の時
        if(array.Length % 2 == 0)
        {
            answer = (array[array.Length / 2] + array[(array.Length / 2) - 1]) / 2;
        }
        else
        {
            answer = array[array.Length / 2];
        }
        
        Console.WriteLine(answer);
        
    }
}