In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Ex Input:
Angiosperms are divided into _ groups- monocots and dicots.

Ex Output:
two

Ex Input:
Porcine insulin has _ different amino acid and bovine insulin has three different amino acids.

Ex Output:
one

Ex Input:
Infertility is fairly common, and about one out of every _ couples is infertile at any given time.

Ex Output:
six