Try to guess 20 (actually, 24 because of massive tie-in on the bottom of the list) first level administrative subdivision capitals (both in Switzerland and other countries) closest to Sarnen.
For practical reasons, I'm making some exceptions in this series. Relevant exception for this quiz is:
For Luxembourg, Liechtenstein, San Marino and Andorra, only country capital and largest (second largest if capital's the largest) municipality seat are included.
If some subdivision capitals are omitted but should be included, please let me know.