using System;

public class Test
{
	public static void Main()
	{
	        int hgt = 5;
            int wdt = 4;
            int[,] a = new int[hgt, wdt];
            for (int y = 0; y < hgt; y++)
              for (int x = 0; x < wdt; x++) 
                a[y, x] = ((x%2)==0?y:(hgt-y-1)) + 1 + x * hgt;

            for (int y = 0; y < hgt; y++) {
              for (int x = 0; x < wdt; x++) 
                    Console.Write(a[y,x] + " ");
                Console.WriteLine();
            }
	}
}