using System;

public class Program

{

    public static void Main()

    {

        int num = 0;

        while(num < 20)

        {

            num = num + 2;

            Console.WriteLine(num + " ");

        }

        Console.WriteLine(" ");

        for(int i = 0; i < 20;)

        {

            i = i + 2;

            Console.WriteLine(i + " ");

        }

    }

}