extracting theNamespace from the xml file

I am working on the XML files in C#.

I want to extact the name space and do some maniplations.

say my xml file looks like this.

        <Content xmlns="http://ABCD.com/sdltridion/schemas/XXXXX">
             <first>ABCD</first>
             <second>DCEF</second>
         </Content>
 

I want to extract Xml namespace from the root tag, ang get the value of XXXXX.

Output needed: XXXXX

Can any one help regarding this.

Thank you.

---