manipulating dynamic set in a loop

GAMS
1

Hi,

This is what I have:

scalar n /1000000/;
Set  i /1*1000000/
       ii(i) ;
ii(i)       = yes  ;

I want to manipulate the dynamic set ‘ii’ in a loop based on the value of ‘n’. Here is more explanation:
→ During the first, both values of ‘ii’ and ‘n’ will not change. I have no problem on how to do 1st loop.
→ During second loop, I am going to update the scalar ‘n’ to become 900000. Then, I want the set ‘ii’ to be 1 through n.
→ During third loop, I am going to update the scalar n to become 800000. And I want the set ‘ii’ to be 1 through n.
→ and so on for the remaining loops.

To put it simply, I need the size of the dynamic set to depend on a scalar. How do I do it?