Protecting range limits
 

Hola,
I need help writing code to protect part of a range given a set of limits.
Example: on a 5 x 5 matrix, given n=3, I need to protect rows 4,5 and columns
4,5. Given n=2, I need to protect rows and columns 3,4,5.
Help is very much appreciated.
Regards,
OMER