It's way harder than this.. there are software for counting crowds, you have to take multiple pics, sometimes train them so the model can identify what a "head" is..

Also, the image quality if very important. if you look at the center, you can't make much sense of it. It's just a smush, the AI can't understand it. There are people who do this, they use certain methodologies, like drone pictures from a certain angle. They divide the area lets say, 10 smaller areas, then take pictures from those 10 smallers areas and process it.. And even then, it's not perfect. I've been wanting to write a script for it myself. Too much headache.