diff --git a/day-18/day-18.py b/day-18/day-18.py
index 81ee48d..3b1bd5b 100644
--- a/day-18/day-18.py
+++ b/day-18/day-18.py
@@ -138,10 +138,10 @@ def part_1(input):
 
 def part_2(input):
     result = 0
-    nbrs = []
+    nbrs = set()
     for line in input:
         line = line.rstrip()
-        nbrs.append(parse(line))
+        nbrs.add(parse(line))
     for n1 in nbrs:
         for n2 in nbrs:
             if n1 == n2: