diff --git a/day-12/day-12.py b/day-12/day-12.py
index 4ac07f6..70980d4 100644
--- a/day-12/day-12.py
+++ b/day-12/day-12.py
@@ -2,22 +2,22 @@
 from pathlib import Path
 
 
-def process_node(node, available_edges, visited):
+def process_node(node, edges, visited):
     num_paths = 0
     if node == "end":
         return 1
     if node.islower():
         visited.add(node)
-    neighbors = [n for e in available_edges if node in e for n in e if n != node]
+    neighbors = [n for e in edges if node in e for n in e if n != node]
     for n in neighbors:
         if n not in visited:
-            num_paths += process_node(n, available_edges, visited)
+            num_paths += process_node(n, edges, visited)
     if node in visited:
         visited.remove(node)
     return num_paths
 
 
-def process_node_twice(node, available_edges, visited, visited_twice):
+def process_node_twice(node, edges, visited, visited_twice):
     num_paths = 0
     if node == "end":
         return 1
@@ -28,10 +28,10 @@ def process_node_twice(node, available_edges, visited, visited_twice):
             visited_twice = node
         else:
             visited.add(node)
-    neighbors = [n for e in available_edges if node in e for n in e if n != node]
+    neighbors = [n for e in edges if node in e for n in e if n != node]
     for n in neighbors:
         if n not in visited or visited_twice != node and n != "start":
-            num_paths += process_node_twice(n, available_edges, visited, visited_twice)
+            num_paths += process_node_twice(n, edges, visited, visited_twice)
     if visited_twice == node:
         visited_twice = None
     elif node in visited:
@@ -41,22 +41,22 @@ def process_node_twice(node, available_edges, visited, visited_twice):
 
 def part_1(input):
     result = 0
-    edges = []
+    edges = set()
     for line in input:
         n_start, n_end = line.strip().split('-')
         e = (n_start, n_end)
-        edges.append(e)
+        edges.add(e)
     result = process_node("start", edges, set())
     print("Part 1 result:", result)
 
 
 def part_2(input):
     result = 0
-    edges = []
+    edges = set()
     for line in input:
         n_start, n_end = line.strip().split('-')
         e = (n_start, n_end)
-        edges.append(e)
+        edges.add(e)
     result = process_node_twice("start", edges, set(), None)
     print("Part 2 result:", result)