Salesforce Apex: Parse XML

Hello! I need the following XML parsed into a response map. The interface should be:

public void populateResponseMap(Map''}
xml = '






2222

1
Usage
USAGE
false

6025829
4321


1111

1
Usage
USAGE
false

6025830
1234

........



'2222'}

Matching is based on the key from responseMap mapped to from the XML, the value in the responseMap should be pulled from the field. The XML can contain up to 200 elements and may or may not have a matching input value.

Any questions please let me know.