diff --git a/day14/part1.py b/day14/part1.py
index 29f6b79..2b75556 100644
--- a/day14/part1.py
+++ b/day14/part1.py
@@ -1,32 +1,27 @@
 #!/usr/bin/env python3
 import re
-from collections import Counter
+from collections import Counter, defaultdict
 
 lines = (x.strip() for x in open("input.txt"))
 first = next(lines)
-
-combinations = Counter(first[a:a+2] for a in range(len(first)-1))
-replacements = dict()
-
 next(lines)
 
+combinations = Counter(first[a:a+2] for a in range(len(first)-1))
+replacements = defaultdict(list)
+
 for line in lines:
-    before, insert = re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups()
-    replacements[before] = (before[0]+insert, insert+before[1])
+    (a, b), insert = re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups()
+    replacements[a+insert].append(a+b)
+    replacements[insert+b].append(a+b)
 
 for _ in range(10):
-    nxt = {}
-    for before, afters in replacements.items():
-        for after in afters:
-            add = combinations.get(before, 0) + nxt.get(after, 0)
-            if add:
-                nxt[after] = add
-    combinations = nxt
+    combinations = {
+        k: sum_val for k, v in replacements.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0
+    }
 
-letters = {}
+letters = Counter(first[0] + first[-1])
 for key, cnt in combinations.items():
     letters[key[0]] = letters.get(key[0], 0) + cnt
     letters[key[1]] = letters.get(key[1], 0) + cnt
 
-print(letters)
-print((max(*letters.values())+1) // 2 - (min(*letters.values())+1) // 2)
+print((max(letters.values()) - min(letters.values())) // 2)
diff --git a/day14/part2.py b/day14/part2.py
index cf76aad..108a613 100644
--- a/day14/part2.py
+++ b/day14/part2.py
@@ -1,34 +1,27 @@
 #!/usr/bin/env python3
 import re
-from collections import Counter
+from collections import Counter, defaultdict
 
 lines = (x.strip() for x in open("input.txt"))
 first = next(lines)
-
-combinations = Counter(first[a:a+2] for a in range(len(first)-1))
-replacements = dict()
-
 next(lines)
 
+combinations = Counter(first[a:a+2] for a in range(len(first)-1))
+replacements = defaultdict(list)
+
 for line in lines:
-    before, insert = re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups()
-    replacements[before] = (before[0]+insert, insert+before[1])
-print(combinations)
+    (a, b), insert = re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups()
+    replacements[a+insert].append(a+b)
+    replacements[insert+b].append(a+b)
 
 for _ in range(40):
-    nxt = {}
-    for before, afters in replacements.items():
-        for after in afters:
-            add = combinations.get(before, 0) + nxt.get(after, 0)
-            if add:
-                nxt[after] = add
-    combinations = nxt
-    print(combinations)
+    combinations = {
+        k: sum_val for k, v in replacements.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0
+    }
 
-letters = {}
+letters = Counter(first[0] + first[-1])
 for key, cnt in combinations.items():
     letters[key[0]] = letters.get(key[0], 0) + cnt
     letters[key[1]] = letters.get(key[1], 0) + cnt
 
-print(letters)
-print((max(*letters.values())+1) // 2 - (min(*letters.values())+1) // 2)
+print((max(letters.values()) - min(letters.values())) // 2)