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

Ex Input:
Induction also operates early in development, even before the _ layered embryo forms.

Ex Output:
three

Ex Input:
Carbon dioxide extinguishes fire by physically attacking all _ points of the fire triangle.

Ex Output:
three

Ex Input:
Burglars attack homes without electronic security _ times more often than homes with a system.

Ex Output:
three