Scripting layout names

Hello everyone,

I wonder if anyone could provide a script to rename layouts?
I currently have files with lot of layouts and am naming them manually. When changes need to be made, the order then gets mixed up and I have to start from the beginning renaming them all.
The name is increases by 10 for every layout as follows: OP10, OP20, OP30 and so on. Would it also be possible that I get a prompt asking from which page number to start from? Sometimes the leading particulars are named i, ii, iii, iv etc, so in this case I would need to start renaming from page 5.
Page 5 would then be OP10, Page 6 OP20 etc.
Thank you , Danny