How Many Different Birds Today?

The birdwatching log lists every sighting — but the same pigeon keeps coming back. 🐦

You get the sightings. Print how many different bird types appeared, in ONE line of code if you can!

Example:

Input: sightings = ["robin", "pigeon", "robin", "jay"] Output: 3

set(sightings) collapses the repeated "robin", leaving {"robin", "pigeon", "jay"} — 3 unique birds.