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

namespace ConsoleApp138
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] nums = Console.ReadLine()
               .Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
               .Select(int.Parse)
               .ToArray();
            if (nums.Length < 2)
            {
                Console.WriteLine(OneDigit(nums));
            }
            if (nums.Length % 2 == 0)
            {

                Console.WriteLine(Even(nums));
            }
        }
        static int OneDigit(int[] nums)
        {
            int res = 0;
            foreach (var item in nums)
            {
                res = item;
            }
            return res;
        }
        static int[] Even(int[] nums)
        {

            int quantity = nums.Length;
            int[] res = new int[quantity];
            for (int i = 0; i < nums.Length; i++)
            {
                if (i == nums.Length / 2 - 1)
                {
                    res[i] = nums[i];
                    res[i + 1] = nums[i + 1];
                }
                nums[i] = res[i];
            }
        }
    }
}