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: the palaeoptera is the group of primitive (basal) winged insects which do not fold the wings back over the abdomen, as neoptera do.
Example Output: palaeoptera

Example Input: odd future is a group of hip hop musicians from los angeles, united states.
Example Output: odd future

Example Input: louise leakey (born 21 march 1972) is a kenyan paleontologist.
Example Output:
louise leakey