// Page 254 #1

import java.util.Scanner;
public class Prog_16_1Even
{
	public static void CountUp ( int num )
	{
		if (num>20)
			System.out.println();
		else
		{
	       System.out.print(num+" ");
	       CountUp(num+2);
	    }
	}

	public static void main(String[] args)
	{
		CountUp(10);
		System.out.println("\n\n");
	}
}