instruction:
This task is about identifying the subject of a given sentence. The subject of a sentence is the person, place, or thing that is performing the action of the sentence. The subject represents what or whom the sentence is about. Each sentence in this task is guaranteed to contain a single subject. The input is a sentence and the output is the identified subject of that sentence.
question:
The nationality of Alan Shepard is United States.
answer:
Alan Shepard


question:
Athens is located in the country of Greece.
answer:
Athens


question:
Alfonso gomez-rejon directed episode number 18 in the series.
answer:

18