class FileWork
    {
        public static Stream BrowseFile()
        {
            OpenFileDialog f = new OpenFileDialog();
            Stream fs = null;
            f.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            f.Filter = "txt files (*.txt)|*.txt";

            if(f.ShowDialog() == DialogResult.OK)
                fs = f.OpenFile();

            return fs;
        }

        public static string ReadFile(Stream fileStream)
        {
            fileStream.Seek(0, SeekOrigin.Begin);
            StreamReader reader = new StreamReader(fileStream);

            return reader.ReadToEnd();
        }

        public static int[,] SaveMatrix(Stream fileStream, int N, int M)
        {
            string file = ReadFile(fileStream);
            string[] fileArr;

            file = file.Remove(0, 5);

            fileArr = file.Split(new Char[] {'\n', '\r'}, StringSplitOptions.RemoveEmptyEntries);

            int len = N * M;
            int[,] matrix = new int[len, len];

            for (int i = 0; i < len; i++)
                for (int j = 0; j < len; j++)
                    matrix[i, j] = (int)Char.GetNumericValue(fileArr[i][j]);

            return matrix;
        }

        public static void GetSize(Stream fileStream, out int N, out int M)
        {
            string file = ReadFile(fileStream);
            string firstNum = "";
            string secondNum = "";
            int i = 0;

            while (!file[i].Equals('\r'))
            {
                while (!file[i].Equals(' '))
                {
                    firstNum += file[i];
                    i++;
                }
                i++;

                while (!file[i].Equals('\r'))
                {
                    secondNum += file[i];
                    i++;
                }
                break;
            }

            N = int.Parse(firstNum);
            M = int.Parse(secondNum);
        }
    }