diff --git a/main.py b/main.py
index eeec124..40a6b06 100644
--- a/main.py
+++ b/main.py
@@ -264,8 +264,8 @@ async def fight(ctx):
 
 
 def score(danbooru_tags: Set[str], interrogator_tags: Set[str]) -> decimal.Decimal:
-    tags_in_danbooru = danbooru_tags | interrogator_tags
-    tags_not_in_danbooru = danbooru_tags - interrogator_tags
+    tags_in_danbooru = danbooru_tags.intersection(interrogator_tags)
+    tags_not_in_danbooru = interrogator_tags - danbooru_tags
     return decimal.Decimal(
         len(tags_in_danbooru) - len(tags_not_in_danbooru)
     ) / decimal.Decimal(len(danbooru_tags))