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\*.

[EX Q]: who played in the men's semi final in wimbledon in 2015
[EX A]: Novak Djokovic

[EX Q]: what does sandstone turn into under heat and pressure
[EX A]: quartzite

[EX Q]: who has the most ko's in boxing
[EX A]:
Billy Bird