The London Racetrack needs to submit its 3 fastest horses to the…

The London Racetrack needs to submit its 3 fastest horses to the Kentucky Derby out of 25 horses. However, all of their information was lost and they don't know any of the horse's times. Similarly, they all look identical so they can't remember who's fastest. They can only race 5 horses at once, so what is the fewest number of races they can conduct to find the 3 fastest horses?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #95499