Don't you know why so few people solved this problem? Because of incorrect statement (at least, its russian version). Read:

"4. Если нужная клавиша была нажата первым шагом в соответствующем степе, и с начала периода прошло менее 40% периода, то игрок получает «PERFECT», менее 70% — «GREAT», и не менее 70% — «GOOD»."

But in tests player gets, for instance, PERFECT, if NOT MORE than 40% of time elapsed (but from the statement STRICTLY LESS). I got AC during the contest only after corecting my program (+4 :((()

This is very bad - errors in statement in realisation problems :(((

See line 25 of your code:
Why do you do this? That is why you need to change "less" to "less or equal".

Edited by author 23.04.2007 18:16

Statements are correct.
I've just AC'ed it, considering that statements are correct.
Maybe you had some problems with float arithmetic?

Fixed. Thanks :)