Skipped the Second Day

Day one of the coding camp was packed; day two, some seats were empty. Who bailed? 🪑

You get day1 and day2 attendance lists. Print the names who came day one but not day two, alphabetical, space-separated — or full house.

Example:

Input: day1 = ["mia", "leo", "kai"], day2 = ["kai", "mia"] Output: leo

set(day1) - set(day2) removes anyone who came both days, leaving just "leo".