diff --git a/day-13/day-13.py b/day-13/day-13.py
index 3dc62e4..6fd0457 100644
--- a/day-13/day-13.py
+++ b/day-13/day-13.py
@@ -3,29 +3,28 @@ from pathlib import Path
 
 
 def fold(i, dots):
-    new_dots = []
-    if i[0] == 'x':
-        for d in dots:
+    new_dots = set()
+    for d in dots:
+        if i[0] == 'x':
             n = (i[1] - abs(d[0] - i[1]), d[1])
-            if d[0] != i[1] and n not in new_dots:
-                new_dots.append(n)
-    elif i[0] == 'y':
-        for d in dots:
+            if d[0] != i[1]:
+                new_dots.add(n)
+        elif i[0] == 'y':
             n = (d[0], i[1] - abs(d[1] - i[1]))
-            if d[1] != i[1] and n not in new_dots:
-                new_dots.append(n)
+            if d[1] != i[1]:
+                new_dots.add(n)
 
     return new_dots
 
 
 def part_1(input):
     result = 0
-    dots = []
+    dots = set()
     instructions = []
     for line in input:
         if ',' in line:
             x, y = line.strip().split(',')
-            dots.append((int(x), int(y)))
+            dots.add((int(x), int(y)))
         elif 'fold along' in line:
             d, c = line.strip().split()[-1].split('=')
             instructions.append([d, int(c)])
@@ -36,12 +35,12 @@ def part_1(input):
 
 def part_2(input):
     result = 0
-    dots = []
+    dots = set()
     instructions = []
     for line in input:
         if ',' in line:
             x, y = line.strip().split(',')
-            dots.append((int(x), int(y)))
+            dots.add((int(x), int(y)))
         elif 'fold along' in line:
             d, c = line.strip().split()[-1].split('=')
             instructions.append([d, int(c)])