using System;

public class Program

{

    static void PrintZigZag(int[,] matrix)

    {

        int row = matrix.GetLength(1);  

        int col = matrix.GetLength(0);

        int even = 0;

        int odd = 1;

        while(even < row)

        {

            for(int i = 0; i < col; i++)

            {

                Console.WriteLine(matrix[even, i]);

            }

            even = even + 2;

            if(odd < row)

            {

                for(int i = col -1; i>= 0; i--)

                {

                        Console.WriteLine(matrix[odd, i]);

                }

                odd = odd + 2;

            }

        }

    }

    public static void Main()

    {

         int[, ] matrix = { { 1, 2, 3 },

                        { 4, 5, 6 },

                        { 7, 8, 9 } };

        PrintZigZag(matrix);

    }

}