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.

Example Input: The ribbons are then twisted up into yarns, and the twist given binds the fibres firmly together so that they hold by friction when the yarn is subjected to strain.
Example Output: The ribbons

Example Input: American hemp is about equal to European hemp, but is not used by the Admiralty.
Example Output: American hemp

Example Input: Were this not done, laying the strands together would tend to untwist the yarns in each strand.
Example Output:
this