using System;

public class Program

{

    public static void Main()

    {

        Random r= new Random();

        int k;

        int [] a = new int[10];

        for(int j = 0;j < 10; j++)

        {

            a[j] = r.Next(1,101);

            Console.Write(a[j] + " ");

        }

        Console.WriteLine();

        for(int i = 0;i < 10; i++)

        {

            if(i%2==1)

            {

                k = a[i];

                a[i] = a[i-1];

                a[i-1] = k;

            }

        }

        for(int l = 0; l < 10; l++)

            Console.Write(a[l] + " ");

    }

}