diff --git a/README.markdown b/README.markdown
index 97efed5..9389bd7 100644
--- a/README.markdown
+++ b/README.markdown
@@ -100,7 +100,7 @@ cd <PATH_TO_ASOTR_CSV>
 or if you already have csv files with ASOTR data, you might use plot script only:  
 ```
 cd <PATH_TO_ASOTR_CSV>/data/
-plot_flight_all.py
+python3 plot_flight_all.py
 ```
 
 ## Output asotr_csv data files description