diff --git a/make_new_gtlds.pl b/make_new_gtlds.pl
index d377f0b..dc7110e 100755
--- a/make_new_gtlds.pl
+++ b/make_new_gtlds.pl
@@ -9,7 +9,7 @@ while (<>) {
 	s/^\s+//; s/\s+$//;
 	next if /^$/;
 
-	die "format error: $_" if not /^((?:xn--)?[a-z0-9]+)$/;
+	die "format error: $_" if not /^(xn--[a-z0-9-]+|[a-z]+)$/;
 
 	print qq|    "$_",\n|;
 }