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.

erzurum is a city in eastern anatolia (asian turkey).
erzurum

mpika district is a district of zambia in the northern province.
mpika district

the title of archduke (feminine: archduchess) (german: "erzherzog", feminine form: "erzherzogin") is a rank above duke and under king.

archduke