The source code a web page is a text file of html format. For example, the following text is a part of the source code of a web page.

<footer>
<div class="width">
<img src="images/footer-logo.png">
<p class="foot-right">© Chang Jung Christian University.All Rights Reserved.Designed by <a href="http://www.weya.com.tw/" target="_blank">Weya</a></p>
<div class="foot-left">
<p>Address : No.1,Changda Rd.,Gueiren District, Tainan City 71101, Taiwan(R.O.C.)</p>
<p> Tel:886-6-2785980　　Fax:886-6-2785979　　Email：[email protected]</p>
</div> <!--_________ foot-span_________-->
</div> <!--_________ width_________-->
</footer>

In the web pages, the phone number consists of number digits and ‘-’ with the format “xxx-x-xxxxxxx” or “xx-xxxxxxx” and always occurs right after the keyword “Tel:”. Please write a program to retrieve the phone number from a web page source code.

網頁的原始碼是html格式的純文字文件。例如，以下文字是某個網頁原始碼的一部分。
<footer>
<div class="width">
<img src="images/footer-logo.png">
<p class="foot-right">© Chang Jung Christian University.All Rights Reserved.Designed by <a href="http://www.weya.com.tw/" target="_blank">Weya</a></p>
<div class="foot-left">
<p>Address : No.1,Changda Rd.,Gueiren District, Tainan City 71101, Taiwan(R.O.C.)</p>
<p> Tel:886-6-2785980　　Fax:886-6-2785979　　Email：[email protected]</p>
</div> <!--_________ foot-span_________-->
</div> <!--_________ width_________-->
</footer>

在網頁中，電話號碼由數字和“-”組成，格式為“xxx-x-xxxxxxx”或“xx-xxxxxxx”，並且始終緊跟在關鍵字“Tel：”之後。 請撰寫程式以從網頁原始碼中取出電話號碼。