diff --git a/src/derivatives.py b/src/derivatives.py
index ba8a59d..9aa4c22 100644
--- a/src/derivatives.py
+++ b/src/derivatives.py
@@ -48,7 +48,7 @@ def filter_data(file: Path) -> pd.DataFrame:
         c1 = 0
         c2 = 0
         if crank==1:
-            d1 = tume_us-c1
+            d1 = time_us-c1
             d2 = d1-(c1-c2)
             if crank_flag:
                 rows.append({