using System;

public class Program

{

    public static void Main()

    {

        int[,] array = new int[4,5] { { 4, 2, 6, 9, 12 }, { 3, 6, 1, 2, 10 }, { 5, 6, 12, 99, 4 }, { 11, 7, 8, 0, 15 } };

        int bigNum = 0;

        foreach(int i in array)

        {

            if(i > bigNum)

            {

                bigNum = i;

            }

        }

        Console.WriteLine(bigNum);

    }

}