How to set input size?

I want to set my input that will take only 1 or 12 or smth else value. How can i set input that inside of input we can write only 1 number for example?

This should be possible to do with events and you could follow the same guidelines I wrote for you here. With different events (onChange, onFocus, onBlur) you could set the bound value of Input to what you want.

You could also use Receive event Flow function to trigger when your bound Input value changed and change its value then.