diff --git a/day21/module.py b/day21/module.py
index 916f8e4..47a812c 100644
--- a/day21/module.py
+++ b/day21/module.py
@@ -58,6 +58,8 @@ def p2(hazzard):
                         hazzard2[i] = list(v.intersection(hazzard2[i]))
                     else:
                         hazzard2[i] = list(v)
+            if i not in hazzard2:
+                hazzard2[i] = hazzard[i]
         hazzard = hazzard2
     print(','.join([x[0] for x in sorted(hazzard.items(), key=lambda x: x[1])]))