Can you explain how the outcome is 3.
As I think answer should be 2 bcz in one step I’ll select the whole substring of length 13 and make required changes, then in the next step I would select substring of length 11 from index 1 to 11(zero based indexing) and make required changes. Thus the answer should be 2.
Also I think there exist no case when the output will be greater than 2.