using System;

public class Program

{

    public static void Main()

    {

        int [] myarray = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

        int i;

        for (i = 0; i < myarray.Length; i++)

        {

            if (i % 2 == 0)

            {

                Console.WriteLine(myarray[i]+2);

            }

            else

            {

                Console.WriteLine(myarray[i]);

            }

        }

    }

}