class Program
{
    static void Main(string[] args)
    {
        string inputCount = Console.ReadLine()!;
        string[] inputNum = Console.ReadLine()!.Split(' ');
        List<double> numList = new List<double>();

        for (int i = 0; i < inputNum.Length; i++)
        {
            numList.Add(double.Parse(inputNum[i]));
        }

        numList.Sort();
        if (numList.Count % 2 == 1)
        {
            Console.WriteLine(numList[numList.Count / 2]);
        }
        else
        {
            double ave = (numList[numList.Count / 2 - 1] + numList[numList.Count / 2]) / 2;
            Console.WriteLine(ave);
        }
    }
}