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:
This rope is made from the leaves of the Agave sisalana plant, which is a member of the cactus family.

Ex Output:
This rope


Ex Input:
Because it is not so reliable as manila it is not used for boats, falls, slings or for any purpose where the parting of the rope may endanger life.

Ex Output:
it


Ex Input:
Next, a certain number of yarns are twisted together to form strands which, at the Admiralty Ropery, Chatham, are usually 150 fathoms in length when completed.

Ex Output:

a certain number of yarns