I viewed the code of Timi66/187299702, shendian304/187337308, they are same with my code, but I also viewed their submission.
Then I found that their codes were skipped: https://mirror.codeforces.com/submissions/shendian304 https://mirror.codeforces.com/submissions/Timi66 
They handed in several copies of codes belonging to different people in a row!
They submit problem A several times, and the code is very diffrent.I think somebody locked the problem and view my code, and copy my code to make me unrated.
There's a talk from system to me:
Attention!
Your solution 187282259 for the problem 1770A significantly coincides with solutions Ling_Cat_/187282259, Timi66/187299702, shendian304/187337308. Such a coincidence is a clear rules violation. Note that unintentional leakage is also a violation. For example, do not use ideone.com with the default settings (public access to your code). If you have conclusive evidence that a coincidence has occurred due to the use of a common source published before the competition, write a comment to post about the round with all the details. More information can be found at http://mirror.codeforces.com/blog/entry/8790. Such violation of the rules may be the reason for blocking your account or other penalties. In case of repeated violations, your account may be blocked.
I think my contest should be rated as normal.
