use XML::XPath;
my $file = 'memlist.xml';
my $xp = XML::XPath->new(filename=>$file);
my $nodeset = $xp->find('/MEMBERLIST/LIST');
                                                                                
my $max_nickid = -1;
my $max_rowid = -1;
                                                                                
foreach my $list ( $nodeset->get_nodelist)
{
    my $nickid = $list->findvalue('NICKID/text()')->value();
    my $rowid = $list->findvalue('ROWID/text()')->value();
                                                                                
    $max_nickid = $nickid if ($nickid > $max_nickid);
    $max_rowid = $rowid if ($rowid > $max_rowid);
}
                                                                                
print "NICK: $max_nickid  ROWID: $max_rowid\n";