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.

Ex Input:
filisur is a former municipality of the district albula in the canton of graubunden in switzerland.

Ex Output:
filisur

Ex Input:
gossliwil is a former municipality in the district bucheggberg, in the canton of solothurn, switzerland.

Ex Output:
gossliwil

Ex Input:
landing craft are small or medium sized boats.

Ex Output:
landing craft