diff --git a/train.py b/train.py
index 4d47bba..804d235 100755
--- a/train.py
+++ b/train.py
@@ -37,7 +37,7 @@ def random_training_set(chunk_len, batch_size):
     inp = torch.LongTensor(batch_size, chunk_len)
     target = torch.LongTensor(batch_size, chunk_len)
     for bi in range(batch_size):
-        start_index = random.randint(0, file_len - chunk_len)
+        start_index = random.randint(0, file_len - chunk_len - 1)
         end_index = start_index + chunk_len + 1
         chunk = file[start_index:end_index]
         inp[bi] = char_tensor(chunk[:-1])