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 social democratic party of germany (german sozialdemokratische partei deutschlands or spd) is the oldest political party in germany that still exists, having been formed on 23 may 1863.
Example Output: social democratic party of germany

Example Input: the centre for conflict and peace studies (abbreviated caps) is an independent research organization, which started in july 2006.
Example Output: centre for conflict and peace studies

Example Input: interstate 49 is an interstate highway in the state of louisiana in the united states.
Example Output:
interstate 49