If you want to take a square root of a square root you will need 2 squares roots,
For example, i want the square root of the square root of 16.
I'll take it first: √16 = 4 and again, √4 = 2
So, the square root of the square root of 16 is 2.
But you can also make a root with index 4.
Because if you do 2.2.2.2 you will take 16.