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: be careful with my heart is a philippine television drama series.
Example Output: be careful with my heart

Example Input: the king of fighters '94 is a 1994 fighting game released by snk for the neo geo arcade and home consoles.
Example Output: the king of fighters

Example Input: a sandwich panel is a kind of composite material, which is usually made of two components: a small outside layer (which is the same on both sides), and an inside layer, which is used to get certain properties, for example insulation or fire resistance.
Example Output:
sandwich panel