How to delete duplicate record from input file?

If i am getting input like below

<Root>

<row>

<field>A</field>

</row>

<row>

<field>B</field>

</row>

<row>

<field>A</field>

</row>

</Root>

Then i want output like this

<Root>

<row>

<field>B</field>

</row>

</Root>

Is it possible through xslt or xsd validation?