diff --git a/2021-python/solutions/day_14.py b/2021-python/solutions/day_14.py
index 6422d99..faee97b 100644
--- a/2021-python/solutions/day_14.py
+++ b/2021-python/solutions/day_14.py
@@ -1,5 +1,5 @@
 from solutions import BaseSolution
-from collections import Counter
+from collections import Counter, defaultdict
 
 
 class Solution(BaseSolution):
@@ -21,28 +21,23 @@ class Solution(BaseSolution):
     def _solve(self, puzzle_input, steps=10):
         polymer, pir = puzzle_input
         pir = dict(pir)
+        pairs = defaultdict(int)
+        chars = defaultdict(int, Counter(polymer))
+        for l, r in zip(polymer[:-1], polymer[1:]):
+            pairs[(l, r)] += 1
         for _ in range(steps):
-            p = []
-            for i in range(len(polymer) - 1):
-                a, b = polymer[i : i + 2]
-                p.append(a)
-                s = pir.get(a + b)
-                if s:
-                    p.append(s)
-            p.append(polymer[-1])
-            polymer = p
-        c = [v for k, v in Counter(polymer).most_common()]
-        return max(c) - min(c)
+            nxt = defaultdict(int)
+            for lr, count in pairs.items():
+                l, r = lr
+                m = pir["".join(lr)]
+                nxt[(l, m)] += count
+                nxt[(m, r)] += count
+                chars[m] += count
+            pairs = nxt
+        cv = chars.values()
+        return max(cv) - min(cv)
 
 
 if __name__ == "__main__":
     solution = Solution()
     solution.show_results()
-
-"""
-Template:     NNCB
-After step 1: NCNBCHB
-After step 2: NBCCNBBBCBHCB
-After step 3: NBBBCNCCNBBNBNBBCHBHHBCHB
-After step 4: NBBNBNBBCCNBCNCCNBBNBBNBBBNBBNBBCBHCBHHNHCBBCBHCB
-"""