diff --git a/y2022/vision/viewer.cc b/y2022/vision/viewer.cc
index f99cf97..82a5e45 100644
--- a/y2022/vision/viewer.cc
+++ b/y2022/vision/viewer.cc
@@ -216,7 +216,7 @@
   TargetEstimator estimator(intrinsics, extrinsics);
 
   for (auto it = file_list.begin() + FLAGS_skip; it < file_list.end(); it++) {
-    LOG(INFO) << "Reading file " << *it;
+    LOG(INFO) << "Reading file " << (it - file_list.begin()) << ": " << *it;
     cv::Mat image_mat = cv::imread(it->c_str());
     BlobDetector::BlobResult blob_result;
     blob_result.binarized_image =