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.

Example Input: chumbawamba were a british alternative rock group.
Example Output: chumbawamba

Example Input: boyz ii men is an american boy band from philadelphia, pennsylvania.
Example Output: boyz ii men

Example Input: hellmuth walter (26 august 1900 in wedel near hamburg – 16 december 1980 in upper montclair, new jersey) was a german engineer.
Example Output:
hellmuth walter