diff --git a/utils/donut_dataset.py b/utils/donut_dataset.py
index 0474a87..6319a0e 100644
--- a/utils/donut_dataset.py
+++ b/utils/donut_dataset.py
@@ -48,7 +48,7 @@ class DonutDataset(Dataset):
         self.added_tokens = added_tokens
 
         self.dataset = dataset
-        self.dataset_length = len(list(self.dataset))
+        self.dataset_length = len(self.dataset)
 
         self.gt_token_sequences = []
         for sample in self.dataset: