import java.util.Scanner;

/*
 * Prints all (or only even) numbers between 1 and N.
 */
public class PrintNumbers
{
	public static void main(String[] args) 
	{	
		int i, num;
		Scanner sc = new Scanner(System.in);
		System.out.print("Enter a number: ");
		num = sc.nextInt(); 
		
		// Print all numbers between 1 and num
		for (i = 1; i <= num; i++)			   
			System.out.println(i);
		
		// Print only even numbers
		System.out.println("\nPrinting only even numbers...");
		/* 
		// Simple solution
		for (i = 1; i <= num; i++)
			   if (i % 2 == 0)
			      System.out.println(i); 
		*/
		// Better solution			
		for (i = 2; i <= num; i=i+2)
		     System.out.println(i); 	
	}
}