using System;

public class Program

{

    public static void Main()

    {

        double[] input= new double[] {double.Parse(Console.ReadLine())};

        double actualmedian = Median(input);

        Console.WriteLine(actualmedian);

    }

static private double Median(double[] array) 

    {

        double [] tempArray = array;

        int count = tempArray.Length;

        Array.Sort(tempArray);

        double medianValue = 0;

        if (count % 2 == 0)

        {

            double middleElement1 = tempArray[(count / 2) - 1];

            double middleElement2 = tempArray[(count / 2)];

            medianValue = (middleElement1 + middleElement2) / 2;

        }

        else

        {

            medianValue = tempArray[(count / 2)];

        }

​

        return medianValue;

    }

    }

​