Generating a sprite sheet in order of the file name?

Hello, i got Animate CC because I was told I can make sprite sheets. When I copy all of the layers -> generate sprite sheet, it puts them in random order. This would be fine but I want to create animations with .css using the spritesheet which is impossible if they are in random orders. I was wondering if it was possible to force them into some kind of order? They are named 1.png 2.png and so on.