Gotta cluster 'em all!

Pokemon Go is a popular mobile game where users find, capture, and train virtual Pokemon characters. These characters are scattered throughout real locations and users have to physically travel to find these characters. Pokemon Go users can battle other users at Pokemon Gyms, which are physical locations with high traffic.

Reported Pokemon sightings in downtown Perth have been plotted according to longitude and latitude. Using clustering and this sighting data, you need to help decide where gyms should open up in downtown Perth.

According to these sightings, how many gyms do you think should be opened up in downtown Perth?