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

namespace laba12_die_die
{
    class Program
    {
        static void Main(string[] args)
        {
            //Task 1
            Console.WriteLine("Task 1");
            Hill();
        }
           
        
        
        
                    public static void Hill() 
            {
                        int n = 0;
                        n = Convert.ToInt32(Console.ReadLine());
                         int[] arr = new int [n];
                         int[] output_arr = new int[n];
                         Random rnd = new Random();
                         for (int i = 0; i < arr.Length; i++)
                      {
                          arr[i] = rnd.Next(20);
                      }

                        for(int i = 0; i<arr.Length;i++)
                        {
                            Console.Write("{0} ", arr[i]);
                        }
                        Console.WriteLine();
                         int kol = 1;
                        bool p;
                        do
                        {
                            p = true;
                            for (int k = 0; k < n - kol; k++)
                                if (arr[k] > arr[k + 1])
                                {
                                    int w = arr[k];
                                    arr[k] = arr[k + 1];
                                    arr[k + 1] = w;
                                    p = false;
                                }
                            kol++;
                        } while (!p);
                        int z = 0;
                        int v = 0;
                        Array.Reverse(arr);
                        int tmp = 0;
        for(int i = 0; i  < arr.Length; i++)
        {
            
            if (tmp == 0)
            {
                output_arr[z] = arr[i];
                tmp = 1;
                z++;
            }
            else
            {
                output_arr[output_arr.Length -1 -v] = arr[i];
                tmp = 0;
                v++;
            }
        
            
        }

        for (int i = 0; i < output_arr.Length; i++)
        {
            Console.Write("{0} ", output_arr[i]);
        }
            Console.ReadLine();
        }
    }
}