In this task, You are given an open-domain question that can be answered based on factual information. Your task is to provide \*short\* answer (in a few words only) for the given question. The short answer can be one or more entities or it can also be boolean \*yes\* or \*no\*.

[Q]: who proposed the modern model of the solar system
[A]: Victor Safronov


[Q]: when did robben island became a world heritage site
[A]: 1999


[Q]: how many nfl championships did the packers win
[A]:
13