DConf 2017 Berlin - bicycles

[Adrian Matoga via Digitalmars-d]

I'm arriving at Berlin Ostbahnhof on Wednesday evening and will 
be heading to Britz Hotel, but last year I learnt that the best 
way to get around the city is on a bicycle. Can you recommend a 
place (preferably near the station) where I could rent a 
not-so-small bike for 4 days for a reasonable price?
Thanks!