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.

Ex Input:
In some countries, and commercially in Great Britain, cordage is sometimes measured by its diameter.

Ex Output:
cordage


Ex Input:
The rope is flexible, durable, strong, and stands up well to wear and weather.

Ex Output:
The rope


Ex Input:
Sisal rope.

Ex Output:

Sisal rope