static void FillMatrix1(int[,] matrix)
    {
        int size = matrix.GetLength(0) * matrix.GetLength(1);
        int row = 0;
        int col = 0;
        for (int i = 1; i <= size; i++)
        {
            matrix[row, col] = i;
            row++;
            if (row == matrix.GetLength(0))
            {
                row = 0;
                col++;
            }
        }
    }