Neopixels max data wire distance

Hi there. What is the maximum theoretical distance between the controller and Neopixel LED strip, given it’s powered where the strip is located and only the data wire needs to be long?

I’d like to control a light display around 30-50 meters away from the control unit. The display would be powered on the spot but the actual data would need to be sent from another building. What would be the best approach?