diff --git a/preprocess-shards.py b/preprocess-shards.py
index 4859799..c9602a5 100644
--- a/preprocess-shards.py
+++ b/preprocess-shards.py
@@ -198,7 +198,7 @@ def convert(srcfile, targetfile, batchsize, seqlength, outfile, total_num_sents,
                     if source_lengths[i] > curr_l:
                         curr_l = source_lengths[i]
                         l_location.append(j+1)
-                l_location.append(len(sources))
+                l_location.append(len(sources)+1)
 
                 #get batch sizes
                 curr_idx = 1