diff --git a/README.md b/README.md
index 31eae80..0c708f9 100644
--- a/README.md
+++ b/README.md
@@ -17,3 +17,5 @@ Dwnload SRG/ART-XC monitor CSV file from https://monitor.srg.cosmos.ru/
 insert filename to plot.py and run ```python plot.py```. Result will be saved to ```monitor.png``` as shown below:
 
 ![ezcv logo](http://heagit.cosmos.ru/artxc/monitor/raw/branch/main/monitor.png)
+
+Vertical dashed line shows a time of interested event.
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