Get Sign / Flag in Calendar Cell

Hello,

Anyone can help me how to get the flag / sign in calendar cell? The example I attached with the blue color box.

image

Thanks in advanced,
Brian H

@henokhbrian

May I know why you need that flag ?

Just for classification, example:
in every datetime have a image data. The datetime which has image data, has also the flag.
And I want to know which datetime hasn’t the flag in their cell.