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:
rakesh sharma (born 13 january 1949) is a retired squadron leader in the indian air force.

Ex Output:
rakesh sharma


Ex Input:
eugenio bersellini (10 june 1936 – 17 september 2017) was an italian football player and manager.

Ex Output:
eugenio bersellini


Ex Input:
mitochondrial dna (mtdna or mdna) is the dna in mitochondria.

Ex Output:

mitochondrial dna