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.

2ne1 is a pop group of female singers from south korea.
2ne1

murray albert olmstead (september 4, 1926 – november 16, 2015) was a canadian professional ice hockey left winger.
bert olmstead

roger mudd (born february 9, 1928) is an american broadcast journalist.

roger mudd