<?xml version="1.0" encoding="ISO-8859-1" ?>

<!ELEMENT results (result)*>

<!ELEMENT result (substitution*)>
<!ELEMENT substitution EMPTY>

<!ATTLIST result solution (yes|no) "yes">
<!ATTLIST result number CDATA #IMPLIED>
<!ATTLIST substitution variable CDATA #REQUIRED>
<!ATTLIST substitution value CDATA #REQUIRED>