reach xml tags under the same name using xpath

I have an xml file with a structure like this:

<xml>

<tag>
<name>paul</name>
<value>1</value>
</tag>

<tag>
<name>mary</name>
<value>2</value>
</tag>

<tag>
<name>john</name>
<value>3</value>
</tag>
<xml>

My question is, how could i reach each tags value tag using xpath?