Matrix Shafling

using System;
using System.Collections.Generic;
using System.Linq;
class MatrixShuffling
{
    static void Main()
    {
        //Read the matrix dimentions from the console
        var dim = Console.ReadLine()
            .Split(" ", StringSplitOptions.RemoveEmptyEntries)
            .Select(long.Parse)
            .ToArray();
        var n = dim[0];
        var m = dim[1];
        var matrix = new string[n, m];

        //Fill the matrix
        for (int i = 0; i < matrix.GetLength(0); i++)
        {
            var a = Console.ReadLine()
                .Split(" ", StringSplitOptions.RemoveEmptyEntries)
                .ToArray();

            for (int j = 0; j < matrix.GetLength(1); j++)
            {
                matrix[i, j] = a[j];
            }
        }

        //var commands = new string[5];
        while (true)
        {
            var commands = Console.ReadLine()
                .Split(" ", StringSplitOptions.RemoveEmptyEntries)
                .ToArray();
            if (commands[0] == "swap")
            {
                if (commands.Length == 5)
                {
                    var y1 = long.Parse(commands[1]);
                    var x1 = long.Parse(commands[2]);
                    var y2 = long.Parse(commands[3]);
                    var x2 = long.Parse(commands[4]);

                    if (!AreDimentionsValid(y1, x1, y2, x2, n, m))
                    {
                        Console.WriteLine("Invalid input!");
                        continue;
                    }

                    //Swapping algorithm
                    string tempValue = matrix[y1, x1];
                    matrix[y1, x1] = matrix[y2, x2];
                    matrix[y2, x2] = tempValue;

                    //Call printing method
                    PrintMatrix(matrix);
                }
                else
                {
                    Console.WriteLine("Invalid input!");
                    continue;
                }

            }
            else if (commands[0] == "END")
            {
                break;
            }
            else
            {
                Console.WriteLine("Invalid input!");
                continue;
            }
        }
    }

    static bool AreDimentionsValid(long y1, long x1, long y2, long x2,
        long rowLength, long colLength)
    {
        bool areValid = true;

        if (x1 < 0 || x1 >= colLength)
        {
            areValid = false;
        }
        else if (x2 < 0 || x2 >= colLength)
        {
            areValid = false;
        }
        else if (y1 < 0 || y1 >= rowLength)
        {
            areValid = false;
        }
        else if (y2 < 0 || y2 >= rowLength)
        {
            areValid = false;
        }

        return areValid;
    }

    static void PrintMatrix(string[,] matrix)
    {
        for (int i = 0; i < matrix.GetLength(0); i++)
        {
            for (int j = 0; j < matrix.GetLength(1); j++)
            {
                Console.Write(matrix[i, j] + " ");
            }
            Console.WriteLine();
        }
    }
}