How to create pagination with letters using codeigniter - codeigniter

Question

Agent controller:
public function index() {
if (!empty($_SESSION['admin'])) {
$data = array(
'page_title' => 'Agent',
'page_name' => 'agent/index',
'result' => $this->agent_model->list_all()
);
$this->load->view('template', $data);
} else {
redirect('login');
}
}
Agent model:
public function list_all() {
$data = 'agent.id,agent.name,agent.mobile,agent.vehicle,agent.address,agent.img_url,agent.category,agent.status,agent.login_status,vehicle.id AS vehicle_id,vehicle.name AS vehicle_name';
$this->db->select($data);
$this->db->from('agent');
$this->db->join('vehicle', 'agent.vehicle=vehicle.id');
return $this->db->get()->result_array();
}
View:
<?php foreach ($result as $value): ?>
<div class="col-md-4 col-sm-4 col-xs-12 profile_details">
<div class="well profile_view">
<div class="col-sm-12">
<h4 class="brief"><i>Digital Strategist</i></h4>
<div class="left col-xs-7">
<p><i class="fa fa-user"></i> Name: <?= $value['name']; ?></p>
<ul class="list-unstyled">
<li><i class="fa fa-building"></i> Vehicle: <?= $value['vehicle_name']; ?></li>
<li><i class="fa fa-phone"></i> Mobile: <?= $value['mobile']; ?> </li><br/>
<div class="onoffswitch">
<input type="hidden" value="<?= $value["id"]; ?>"/>
<input type="checkbox" class="js-switch"
<?php if ($value['status'] == 1) {
echo "checked";
} ?>>
</div>
</ul>
</div>
<div class="right col-xs-5 text-center">
<img src="/<?= $value['img_url']; ?>" alt="" class="img-circle img-responsive" style="height: 120px; width: 120px;">
</div>
</div>
<div class="col-xs-12 bottom text-center">
<div class="col-xs-12 col-sm-6 emphasis">
<p class="ratings">
<a>4.0</a>
<span class="fa fa-star"></span>
<span class="fa fa-star"></span>
<span class="fa fa-star"></span>
<span class="fa fa-star"></span>
<span class="fa fa-star-o"></span>
</p>
</div>
<div class="col-xs-12 col-sm-6 emphasis btn-group">
<?php if ($value['status'] == 1): ?>
<i class="glyphicon glyphicon-pencil"> </i> Edit
<?php else: ?>
<i class="glyphicon glyphicon-pencil"> </i> Edit
<?php endif; ?>
<a href="<?= base_url("agent/detail/{$value['id']}"); ?>" class="btn btn-primary btn-xs">
<i class="fa fa-user"> </i> View Profile </a>
</div>
</div>
</div>
</div>
<?php endforeach; ?>
Below Screenshot:
Screenshot
MY Question: How to create pagination with letters in codeigniter.
MY Question: I create agent module and i apply pagination with letters in above Screenshot. so how to apply pagination with letters in above view.