Just as you figure out the number, an elf comes running towards you. Apparently they've found another location, by the river, at which you could get another star. Seeing how excited you are, they hasten to clarify that they think it'd have only been possible to get a star there two years ago, and that it's not possible now. You're somewhat unsure what to do next.
Suddenly, you see something that will let you get another star. What is it?
This problem has no input and doesn't require you to write any code.