How is n-m=0 in the video

How is n-m =0 at timestamp 2:42

n-m <= 100000 which is given in the question.

but in the video prateek bhaiya told that m=50 and n=100 therefore n-m should be 50, but video says it is 0

He might have wanted to say something different or He might have mistaken it. It would be the difference between n and m.