Tonight there was a serious technical failure: Codeforces and related infrastructure hard drives have been corrupted. Unfortunately, it turned out that in contrast to all other components, the Codeforces database was not replicated properly. Polygon and Gym files were not injured. However, the Codeforces data has been significantly damaged. 

Most likely, we will be forced to roll back the system to the state on February 7. It will remove 22 days of Codeforces life. Immediate efforts will be directed at the total exclusion of such situations. This is a very serious loss for me personally, which I can only blame myself. 

MikeMirzayanov