reading child tags from xml file

Question

<counries>
 <country name="India" id="1">
  <state name="Gujarat"  id="1">
   <city name="ahmedabad" id="1"></city>
   <city name="baroda" id="2"></city>
  </state>
  <state name="Maharastra"  id="1">
   <city name="mumbai" id="1"></city>
   <city name="pune" id="2"></city>
  </state>
 </country>
 <country name="USA" id="1">
  <state name="Washington"  id="1">
   <city name="othello" id="1"></city>
   <city name="new port" id="2"></city>
  </state>
  <state name="NewYork"  id="1">
   <city name="geneva" id="1"></city>
   <city name="new york" id="2"></city>
  </state>
 </country>
</counries>
this is my xml file. i want to fill 3 dropdownboxes 1st with countries,2nd with its respective states,3rd with its respective cities. in asp.net 3.5 with c#
how should i do it? help me.