Unique value from a list in xslt

Question

From below xml I want to pick only distinct values using xslt

 

Example data:

 

<student1>

<skills>

<skill>ASP</skill>

<skill>SQL</skill> 

<skill>ASP</skill> 

<skill>ASP.net</skill> 

<skill>WCF</skill> 

<skill>ASP</skill>  

</skills> 

</student1> 

 

<student2>

<skills>

<skill>Java</skill>

<skill>Sql</skill>

<skill>jQuery</skill>

<skill>HTML</skill>

<skill>Java</skill>

</skills>

</student2>

 

 

Expected result

 

 

<student1>

<skills>

<skill>ASP</skill>

<skill>SQL</skill>

<skill>ASP.net</skill>

<skill>WCF</skill>

</skills>

</student1>

 

<student2>

<skills>

<skill>Java</skill>

<skill>Sql</skill>

<skill>jQuery</skill>

<skill>HTML</skill>

</skills>

</student2>

 

Please help me on this