It's the first time for me to take part in a div3 contest(Codeforces Round #644 (Div. 3), Rated for me, my official rank is 12) and got +800.Now my rating is 2300! The rating change is absolutely wrong and I found one possible cause of it. Let me share it: As Mike has released the new rating change rule, it's not very hard for us to find out that if an unrated account did very well in the contest, it will get +800 (500 for the first contest and add another 300). However, this added rating is now added on the rating 1500, so it goes wrong. So all in all, the two possible problems I considered are: 1.The rating is added to the original rating 1500 instead of 0. 2.Our original rating was considered as 0 instead on 1500 while being calculated. (Sorry for my english if there are grammar mistakes or missspellings. And maybe my rating has come back to normal when you see this.)