Detailed Instructions: In this task, you are given a sentence. You must find the primary subject in the supplied sentence. The output must be a sub-sequence in the sentence.
See one example below:
Problem: Rope and its Usage
Solution: Rope
Explanation: The word 'Rope' is the key subject here, while Usage is a property of Rope.

Problem: In particularly rough weather, the ship's side should be well fendered.
Solution:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
 the ship's side