diff --git a/day14/part1.py b/day14/part1.py
index 2b75556..0f70d77 100644
--- a/day14/part1.py
+++ b/day14/part1.py
@@ -1,27 +1,24 @@
 #!/usr/bin/env python3
 import re
-from collections import Counter, defaultdict
+from collections import Counter
+from itertools import groupby
+from operator import itemgetter
 
 lines = (x.strip() for x in open("input.txt"))
 first = next(lines)
 next(lines)
 
+repl = (re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups() for line in lines)
+repl = (v for (a, b), insert in repl for v in [(a + insert, a + b), (insert + b, a + b)])
+repl = {k: list(map(itemgetter(1), v)) for k, v in groupby(sorted(repl), itemgetter(0))}
+
 combinations = Counter(first[a:a+2] for a in range(len(first)-1))
-replacements = defaultdict(list)
-
-for line in lines:
-    (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):
-    combinations = {
-        k: sum_val for k, v in replacements.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0
-    }
+    combinations = {k: sum_val for k, v in repl.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0}
 
-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
+letters = ((l, cnt) for key, cnt in combinations.items() for l in key)
+letters = {k: sum(map(itemgetter(1), v)) for k, v in groupby(sorted(letters), itemgetter(0))}
+letters[first[0]] += 1
+letters[first[-1]] += 1
 
 print((max(letters.values()) - min(letters.values())) // 2)
diff --git a/day14/part2.py b/day14/part2.py
index 108a613..f79f5f7 100644
--- a/day14/part2.py
+++ b/day14/part2.py
@@ -1,27 +1,24 @@
 #!/usr/bin/env python3
 import re
-from collections import Counter, defaultdict
+from collections import Counter
+from itertools import groupby
+from operator import itemgetter
 
 lines = (x.strip() for x in open("input.txt"))
 first = next(lines)
 next(lines)
 
+repl = (re.match(r"([A-Z]{2}) -> ([A-Z])", line).groups() for line in lines)
+repl = (v for (a, b), insert in repl for v in [(a + insert, a + b), (insert + b, a + b)])
+repl = {k: list(map(itemgetter(1), v)) for k, v in groupby(sorted(repl), itemgetter(0))}
+
 combinations = Counter(first[a:a+2] for a in range(len(first)-1))
-replacements = defaultdict(list)
-
-for line in lines:
-    (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):
-    combinations = {
-        k: sum_val for k, v in replacements.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0
-    }
+    combinations = {k: sum_val for k, v in repl.items() if (sum_val := sum(combinations.get(x, 0) for x in v)) > 0}
 
-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
+letters = ((l, cnt) for key, cnt in combinations.items() for l in key)
+letters = {k: sum(map(itemgetter(1), v)) for k, v in groupby(sorted(letters), itemgetter(0))}
+letters[first[0]] += 1
+letters[first[-1]] += 1
 
 print((max(letters.values()) - min(letters.values())) // 2)