diff --git a/src/holt59/aoc/2024/day11.py b/src/holt59/aoc/2024/day11.py
index fea35bf..2f541f2 100644
--- a/src/holt59/aoc/2024/day11.py
+++ b/src/holt59/aoc/2024/day11.py
@@ -4,6 +4,13 @@ from typing import Any, Iterator
 from ..base import BaseSolver
 
 
+def n_digits(n: int) -> int:
+    c = int(n == 0)
+    while n > 0:
+        c, n = c + 1, n // 10
+    return c
+
+
 @cache
 def blink_one_stone(stone: int, round: int) -> int:
     if round == 0:
@@ -12,10 +19,10 @@ def blink_one_stone(stone: int, round: int) -> int:
     if stone == 0:
         return blink_one_stone(1, round - 1)
 
-    if len((stone_s := str(stone))) % 2 == 0:
-        n = len(stone_s)
-        return blink_one_stone(int(stone_s[: n // 2]), round - 1) + blink_one_stone(
-            int(stone_s[n // 2 :]), round - 1
+    if (n := n_digits(stone)) % 2 == 0:
+        p = 10 ** (n // 2)
+        return blink_one_stone(stone // p, round - 1) + blink_one_stone(
+            stone % p, round - 1
         )
 
     return blink_one_stone(stone * 2024, round - 1)