diff --git a/day09/part3.py b/day09/part3.py
index 576d0cb..7c87a08 100644
--- a/day09/part3.py
+++ b/day09/part3.py
@@ -1,7 +1,5 @@
 #!/usr/bin/env python3
-import math
 from math import comb
-
 from tqdm import tqdm
 
 lines = (x.strip() for x in open("input.txt"))
@@ -13,7 +11,7 @@ for line in tqdm(lines, total=200):
     for _ in range(365*5):
         numbers.append(sum(factor*val for factor, val in zip(combinations, numbers)))
         combinations.append(-1)
-        combinations = [-combinations[0] if i == 0 else combinations[i-1]-combinations[i] for i in range(len(combinations))]
+        combinations = [(combinations[i-1] if i > 0 else 0)-combinations[i] for i in range(len(combinations))]
     result += numbers[-1]
 
 print(result)