diff --git a/README.md b/README.md
index faff444..c74db81 100644
--- a/README.md
+++ b/README.md
@@ -45,8 +45,7 @@ $ python ./scripts/preprocess_pix2pix_data.py \
     --src data/cityscapes/original/leftImg8bit \
     --dst data/cityscapes/256x256 \
     --size 256 \
-    --random-flip \
-    --random-rotate
+    --random-flip
 ```
 
 ### Maps
diff --git a/scripts/preprocess_pix2pix_data.py b/scripts/preprocess_pix2pix_data.py
index 442008d..af8ac81 100644
--- a/scripts/preprocess_pix2pix_data.py
+++ b/scripts/preprocess_pix2pix_data.py
@@ -24,10 +24,10 @@ def main():
         src_dir = os.path.join(args.src, mode)
         dst_dir = os.path.join(args.dst, mode)
 
-        items = [
-            os.path.join(src_dir, name)
-            for name in os.listdir(src_dir)
-        ]
+        items = []
+        for path, dir, files in os.walk(src_dir):
+            for file in files:
+                items.append(os.path.join(path, file))
 
         index = 0
         print('Processing %s...' % mode)