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

namespace ConsoleApplication14
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
             int b = 0;
              int m = 0;
            int[] a = new int[n];
            
            
            
            for (int i = 0; i < n - 1; i++)
            {
                if (a[i] > a[i+1])
                    {
                        t = a[i+1];
                        a[i+1] = a[i];
                        a[i] = b;
                    }
            }
              m = n / 2;
                 m = a[m];

            Console.WriteLine(m);
            Console.ReadKey();
        }
    }
}

