Minecraft a signal every three pulses?

I'm looking for a simple and compact way to give all three redstone input signals an output. Can you imagine how: if you press a button three times, the redstone cable should blink once. Unfortunately I can't find a suitable search term for google, but I don't know the redstone terms either.

I know that you could solve this with three storage cells (flask plus sand) in a row, but I don't have enough space for that… It doesn't matter in depth, but it should be kept small in width / length…

If possible, the system should be compatible with 1.14, but is not mandatory.

I hope you can help me…

Regards 👋

PS / FunFact: Actually, I need this to power a notepad in front of an observer, then to move this notepad using a piston and finally to return it to the starting position without creating a loop or having to press the notepad several times. In the end it should be a kind of door where the passage through the music blocks is blocked…

Dropper + Hopper.

There are 3 unstackable items in the dropper e.g. Wooden shovels
The dropper points into a hopper, which in turn points into the dropper.
The hopper is blocked by a redstone torch so that nothing flows into the dropper
You measure a signal from the hopper using a comparator. From this you subtract a signal of strength 8 - so that it only gives a signal when all three items are in the hopper
If the comparator then outputs a signal, this is your output. With this output you also have to briefly deactivate the redstone torch on the hopper so that all 3 items flow back