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:
Rot-proofing neither weakens the rope nor increases its weight, but makes it watertight to the extent that, when wet, it absorbs hardly any water and is nearly as light and as easily handled as when it is dry.

Ex Output:
Rot-proofing


Ex Input:
It is very hairy, and brown in colour.

Ex Output:
It


Ex Input:
Weight, breaking strength and methods of supply will be found in Volume II.

Ex Output:

Weight, breaking strength and methods of supply