Ok, thanks!

If the year is 2001, this code still provides the correct answer.

there is smth i want to point on:
what if the year is 2001?
But still it's a nice code !

mastercalss

I wrote down on a sheet of paper and started calculation ! and yea its right !

awesome, i never would have thought of it that way.

Yes, this is wrong according to the program specification—that's not being slightly picky at all! It's a common error class that you need to watch out for because it can have real consequences, for example if you set about building a fence and find yourself one post short:

https://en.wikipedia.org/wiki/Off-by-one_error

Slightly picky but should be >=100 as the requirement is 'at least 100 at_bats'