Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

Input: Consider Input: christian lous lange (september 17, 1869 december 11, 1938) was a norwegian historian, teacher, and political scientist.

Output: christian lous lange

Input: Consider Input: the beethoven house (german: beethoven-haus) in bonn, germany, is a memorial site, museum and cultural institution serving various purposes.

Output: beethoven house

Input: Consider Input: ammonium carbonate, also known as baker's ammonia or sal volatile, is a chemical compound.
Output: ammonium carbonate